Isolation, characterization, and identification of biological control agent for potato soft rot in Bangladesh.

PubMed

Rahman, M M; Ali, M E; Khan, A A; Akanda, A M; Uddin, Md Kamal; Hashim, U; Abd Hamid, S B

2012-01-01

A total of 91 isolates of probable antagonistic bacteria of potato soft rot bacterium Erwinia carotovora subsp. carotovora (Ecc) were extracted from rhizospheres and endophytes of various crop plants, different soil varieties, and atmospheres in the potato farming areas of Bangladesh. Antibacterial activity of the isolated probable antagonistic bacteria was tested in vitro against the previously identified most common and most virulent soft rot causing bacterial strain Ecc P-138. Only two isolates E-45 and E-65 significantly inhibited the in vitro growth of Ecc P-138. Physiological, biochemical, and carbon source utilization tests identified isolate E-65 as a member of the genus Bacillus and the isolate E-45 as Lactobacillus sp. The stronger antagonistic activity against Ecc P-138 was found in E-65 in vitro screening and storage potatoes. E-65 reduced the soft rot infection to 22-week storage potatoes of different varieties by 32.5-62.5% in model experiment, demonstrating its strong potential to be used as an effective biological control agent for the major pectolytic bacteria Ecc. The highest (62.5%) antagonistic effect of E-65 was observed in the Granola and the lowest (32.7%) of that was found in the Cardinal varieties of the Bangladeshi potatoes. The findings suggest that isolate E-65 could be exploited as a biocontrol agent for potato tubers.

Isolation, Characterization, and Identification of Biological Control Agent for Potato Soft Rot in Bangladesh

PubMed Central

Rahman, M. M.; Ali, M. E.; Khan, A. A.; Akanda, A. M.; Uddin, Md. Kamal; Hashim, U.; Abd Hamid, S. B.

2012-01-01

A total of 91 isolates of probable antagonistic bacteria of potato soft rot bacterium Erwinia carotovora subsp. carotovora (Ecc) were extracted from rhizospheres and endophytes of various crop plants, different soil varieties, and atmospheres in the potato farming areas of Bangladesh. Antibacterial activity of the isolated probable antagonistic bacteria was tested in vitro against the previously identified most common and most virulent soft rot causing bacterial strain Ecc P-138. Only two isolates E-45 and E-65 significantly inhibited the in vitro growth of Ecc P-138. Physiological, biochemical, and carbon source utilization tests identified isolate E-65 as a member of the genus Bacillus and the isolate E-45 as Lactobacillus sp. The stronger antagonistic activity against Ecc P-138 was found in E-65 in vitro screening and storage potatoes. E-65 reduced the soft rot infection to 22-week storage potatoes of different varieties by 32.5–62.5% in model experiment, demonstrating its strong potential to be used as an effective biological control agent for the major pectolytic bacteria Ecc. The highest (62.5%) antagonistic effect of E-65 was observed in the Granola and the lowest (32.7%) of that was found in the Cardinal varieties of the Bangladeshi potatoes. The findings suggest that isolate E-65 could be exploited as a biocontrol agent for potato tubers. PMID:22645446

Evolution of novel wood decay mechanisms in Agaricales revealed by the genome sequences of Fistulina hepatica and Cylindrobasidium torrendii

DOE PAGES

Floudas, Dimitrios; Held, Benjamin W.; Riley, Robert; ...

2015-02-12

Wood decay mechanisms in Agaricomycotina have been traditionally separated in two categories termed white and brown rot. Recently the accuracy of such a dichotomy has been questioned. In this paper, we present the genome sequences of the white-rot fungus Cylindrobasidium torrendii and the brown-rot fungus Fistulina hepatica both members of Agaricales, combining comparative genomics and wood decay experiments. C. torrendii is closely related to the white-rot root pathogen Armillaria mellea, while F. hepatica is related to Schizophyllum commune, which has been reported to cause white rot. Our results suggest that C. torrendii and S. commune are intermediate between white-rot andmore » brown-rot fungi, but at the same time they show characteristics of decay that resembles soft rot. Both species cause weak wood decay and degrade all wood components but leave the middle lamella intact. Their gene content related to lignin degradation is reduced, similar to brown-rot fungi, but both have maintained a rich array of genes related to carbohydrate degradation, similar to white-rot fungi. These characteristics appear to have evolved from white-rot ancestors with stronger ligninolytic ability. F. hepatica shows characteristics of brown rot both in terms of wood decay genes found in its genome and the decay that it causes. However, genes related to cellulose degradation are still present, which is a plesiomorphic characteristic shared with its white-rot ancestors. Four wood degradation-related genes, homologs of which are frequently lost in brown-rot fungi, show signs of pseudogenization in the genome of F. hepatica. These results suggest that transition toward a brown-rot lifestyle could be an ongoing process in F. hepatica. Finally, our results reinforce the idea that wood decay mechanisms are more diverse than initially thought and that the dichotomous separation of wood decay mechanisms in Agaricomycotina into white rot and brown rot should be revisited.« less

Evolution of novel wood decay mechanisms in Agaricales revealed by the genome sequences of Fistulina hepatica and Cylindrobasidium torrendii

DOE Office of Scientific and Technical Information (OSTI.GOV)

Floudas, Dimitrios; Held, Benjamin W.; Riley, Robert

Wood decay mechanisms in Agaricomycotina have been traditionally separated in two categories termed white and brown rot. Recently the accuracy of such a dichotomy has been questioned. In this paper, we present the genome sequences of the white-rot fungus Cylindrobasidium torrendii and the brown-rot fungus Fistulina hepatica both members of Agaricales, combining comparative genomics and wood decay experiments. C. torrendii is closely related to the white-rot root pathogen Armillaria mellea, while F. hepatica is related to Schizophyllum commune, which has been reported to cause white rot. Our results suggest that C. torrendii and S. commune are intermediate between white-rot andmore » brown-rot fungi, but at the same time they show characteristics of decay that resembles soft rot. Both species cause weak wood decay and degrade all wood components but leave the middle lamella intact. Their gene content related to lignin degradation is reduced, similar to brown-rot fungi, but both have maintained a rich array of genes related to carbohydrate degradation, similar to white-rot fungi. These characteristics appear to have evolved from white-rot ancestors with stronger ligninolytic ability. F. hepatica shows characteristics of brown rot both in terms of wood decay genes found in its genome and the decay that it causes. However, genes related to cellulose degradation are still present, which is a plesiomorphic characteristic shared with its white-rot ancestors. Four wood degradation-related genes, homologs of which are frequently lost in brown-rot fungi, show signs of pseudogenization in the genome of F. hepatica. These results suggest that transition toward a brown-rot lifestyle could be an ongoing process in F. hepatica. Finally, our results reinforce the idea that wood decay mechanisms are more diverse than initially thought and that the dichotomous separation of wood decay mechanisms in Agaricomycotina into white rot and brown rot should be revisited.« less

Evolution of novel wood decay mechanisms in Agaricales revealed by the genome sequences of Fistulina hepatica and Cylindrobasidium torrendii

PubMed Central

Floudas, Dimitrios; Held, Benjamin W.; Riley, Robert; Nagy, Laszlo G.; Koehler, Gage; Ransdell, Anthony S.; Younus, Hina; Chow, Julianna; Chiniquy, Jennifer; Lipzen, Anna; Tritt, Andrew; Sun, Hui; Haridas, Sajeet; LaButti, Kurt; Ohm, Robin A.; Kües, Ursula; Blanchette, Robert A.; Grigoriev, Igor V.; Minto, Robert E.; Hibbett, David S.

2015-01-01

Wood decay mechanisms in Agaricomycotina have been traditionally separated in two categories termed white and brown rot. Recently the accuracy of such a dichotomy has been questioned. Here, we present the genome sequences of the white rot fungus Cylindrobasidium torrendii and the brown rot fungus Fistulina hepatica both members of Agaricales, combining comparative genomics and wood decay experiments. Cylindrobasidium torrendii is closely related to the white-rot root pathogen Armillaria mellea, while F. hepatica is related to Schizophyllum commune, which has been reported to cause white rot. Our results suggest that C. torrendii and S. commune are intermediate between white-rot and brown-rot fungi, but at the same time they show characteristics of decay that resembles soft rot. Both species cause weak wood decay and degrade all wood components but leave the middle lamella intact. Their gene content related to lignin degradation is reduced, similar to brown-rot fungi, but both have maintained a rich array of genes related to carbohydrate degradation, similar to white-rot fungi. These characteristics appear to have evolved from white-rot ancestors with stronger ligninolytic ability. Fistulina hepatica shows characteristics of brown rot both in terms of wood decay genes found in its genome and the decay that it causes. However, genes related to cellulose degradation are still present, which is a plesiomorphic characteristic shared with its white-rot ancestors. Four wood degradation-related genes, homologs of which are frequently lost in brown-rot fungi, show signs of pseudogenization in the genome of F. hepatica. These results suggest that transition towards a brown rot lifestyle could be an ongoing process in F. hepatica. Our results reinforce the idea that wood decay mechanisms are more diverse than initially thought and that the dichotomous separation of wood decay mechanisms in Agaricomycotina into white rot and brown rot should be revisited. PMID:25683379

Evolution of novel wood decay mechanisms in Agaricales revealed by the genome sequences of Fistulina hepatica and Cylindrobasidium torrendii.

PubMed

Floudas, Dimitrios; Held, Benjamin W; Riley, Robert; Nagy, Laszlo G; Koehler, Gage; Ransdell, Anthony S; Younus, Hina; Chow, Julianna; Chiniquy, Jennifer; Lipzen, Anna; Tritt, Andrew; Sun, Hui; Haridas, Sajeet; LaButti, Kurt; Ohm, Robin A; Kües, Ursula; Blanchette, Robert A; Grigoriev, Igor V; Minto, Robert E; Hibbett, David S

2015-03-01

Wood decay mechanisms in Agaricomycotina have been traditionally separated in two categories termed white and brown rot. Recently the accuracy of such a dichotomy has been questioned. Here, we present the genome sequences of the white-rot fungus Cylindrobasidium torrendii and the brown-rot fungus Fistulina hepatica both members of Agaricales, combining comparative genomics and wood decay experiments. C. torrendii is closely related to the white-rot root pathogen Armillaria mellea, while F. hepatica is related to Schizophyllum commune, which has been reported to cause white rot. Our results suggest that C. torrendii and S. commune are intermediate between white-rot and brown-rot fungi, but at the same time they show characteristics of decay that resembles soft rot. Both species cause weak wood decay and degrade all wood components but leave the middle lamella intact. Their gene content related to lignin degradation is reduced, similar to brown-rot fungi, but both have maintained a rich array of genes related to carbohydrate degradation, similar to white-rot fungi. These characteristics appear to have evolved from white-rot ancestors with stronger ligninolytic ability. F. hepatica shows characteristics of brown rot both in terms of wood decay genes found in its genome and the decay that it causes. However, genes related to cellulose degradation are still present, which is a plesiomorphic characteristic shared with its white-rot ancestors. Four wood degradation-related genes, homologs of which are frequently lost in brown-rot fungi, show signs of pseudogenization in the genome of F. hepatica. These results suggest that transition toward a brown-rot lifestyle could be an ongoing process in F. hepatica. Our results reinforce the idea that wood decay mechanisms are more diverse than initially thought and that the dichotomous separation of wood decay mechanisms in Agaricomycotina into white rot and brown rot should be revisited. Copyright © 2015 Elsevier Inc. All rights reserved.

Report of postharvest rot of kiwifruit in Korea caused by Sclerotinia sclerotiorum.

PubMed

Lee, Jung Han; Kwon, Young Ho; Kwack, Yong-Bum; Kwak, Youn-Sig

2015-08-03

In May 2014, sclerotinia rot symptoms caused by Sclerotinia sclerotiorum were observed on stored kiwifruit in Jinju, South Korea. The symptoms appeared as soft, water-soaked lesions on fruit covered with a white mycelium. The morphological characteristics and the internal transcribed spacer sequences of rRNA of the pathogen isolated from the sclerotinia rot showed it to be S. sclerotiorum. This was confirmed by performing a pathogenicity test with pure cultures of S. sclerotiorum and by reisolating S. sclerotiorum from artificially inoculated kiwifruits. Our results should help promote a better understanding of the diseases that affect kiwifruit and improve practices for postharvest disease control in the kiwifruit industry. Copyright © 2015 Elsevier B.V. All rights reserved.

Revised Phylogeny and Novel Horizontally Acquired Virulence Determinants of the Model Soft Rot Phytopathogen Pectobacterium wasabiae SCC3193

PubMed Central

Koskinen, Patrik; Nokso-Koivisto, Jussi; Pasanen, Miia; Broberg, Martin; Plyusnin, Ilja; Törönen, Petri; Holm, Liisa; Pirhonen, Minna; Palva, E. Tapio

2012-01-01

Soft rot disease is economically one of the most devastating bacterial diseases affecting plants worldwide. In this study, we present novel insights into the phylogeny and virulence of the soft rot model Pectobacterium sp. SCC3193, which was isolated from a diseased potato stem in Finland in the early 1980s. Genomic approaches, including proteome and genome comparisons of all sequenced soft rot bacteria, revealed that SCC3193, previously included in the species Pectobacterium carotovorum, can now be more accurately classified as Pectobacterium wasabiae. Together with the recently revised phylogeny of a few P. carotovorum strains and an increasing number of studies on P. wasabiae, our work indicates that P. wasabiae has been unnoticed but present in potato fields worldwide. A combination of genomic approaches and in planta experiments identified features that separate SCC3193 and other P. wasabiae strains from the rest of soft rot bacteria, such as the absence of a type III secretion system that contributes to virulence of other soft rot species. Experimentally established virulence determinants include the putative transcriptional regulator SirB, two partially redundant type VI secretion systems and two horizontally acquired clusters (Vic1 and Vic2), which contain predicted virulence genes. Genome comparison also revealed other interesting traits that may be related to life in planta or other specific environmental conditions. These traits include a predicted benzoic acid/salicylic acid carboxyl methyltransferase of eukaryotic origin. The novelties found in this work indicate that soft rot bacteria have a reservoir of unknown traits that may be utilized in the poorly understood latent stage in planta. The genomic approaches and the comparison of the model strain SCC3193 to other sequenced Pectobacterium strains, including the type strain of P. wasabiae, provides a solid basis for further investigation of the virulence, distribution and phylogeny of soft rot bacteria and, potentially, other bacteria as well. PMID:23133391

Interactions of Salmonella enterica Serovar Typhimurium and Pectobacterium carotovorum within a Tomato Soft Rot.

PubMed

George, Andrée S; Cox, Clayton E; Desai, Prerak; Porwollik, Steffen; Chu, Weiping; de Moraes, Marcos H; McClelland, Michael; Brandl, Maria T; Teplitski, Max

2018-03-01

Salmonella spp. are remarkably adaptable pathogens, and this adaptability allows these bacteria to thrive in a variety of environments and hosts. The mechanisms with which these pathogens establish within a niche amid the native microbiota remain poorly understood. Here, we aimed to uncover the mechanisms that enable Salmonella enterica serovar Typhimurium strain ATCC 14028 to benefit from the degradation of plant tissue by a soft rot plant pathogen, Pectobacterium carotovorum The hypothesis that in the soft rot, the liberation of starch (not utilized by P. carotovorum ) makes this polymer available to Salmonella spp., thus allowing it to colonize soft rots, was tested first and proven null. To identify the functions involved in Salmonella soft rot colonization, we carried out transposon insertion sequencing coupled with the phenotypic characterization of the mutants. The data indicate that Salmonella spp. experience a metabolic shift in response to the changes in the environment brought on by Pectobacterium spp. and likely coordinated by the csrBC small regulatory RNA. While csrBC and flhD appear to be of importance in the soft rot, the global two-component system encoded by barA sirA (which controls csrBC and flhDC under laboratory conditions) does not appear to be necessary for the observed phenotype. Motility and the synthesis of nucleotides and amino acids play critical roles in the growth of Salmonella spp. in the soft rot. IMPORTANCE Outbreaks of produce-associated illness continue to be a food safety concern. Earlier studies demonstrated that the presence of phytopathogens on produce was a significant risk factor associated with increased Salmonella carriage on fruits and vegetables. Here, we genetically characterize some of the requirements for interactions between Salmonella and phytobacteria that allow Salmonella spp. to establish a niche within an alternate host (tomato). Pathways necessary for nucleotide synthesis, amino acid synthesis, and motility are identified as contributors to the persistence of Salmonella spp. in soft rots. Copyright © 2018 George et al.

Interactions of Salmonella enterica Serovar Typhimurium and Pectobacterium carotovorum within a Tomato Soft Rot

PubMed Central

Cox, Clayton E.; Desai, Prerak; Porwollik, Steffen; Chu, Weiping; de Moraes, Marcos H.; McClelland, Michael; Brandl, Maria T.; Teplitski, Max

2017-01-01

ABSTRACT Salmonella spp. are remarkably adaptable pathogens, and this adaptability allows these bacteria to thrive in a variety of environments and hosts. The mechanisms with which these pathogens establish within a niche amid the native microbiota remain poorly understood. Here, we aimed to uncover the mechanisms that enable Salmonella enterica serovar Typhimurium strain ATCC 14028 to benefit from the degradation of plant tissue by a soft rot plant pathogen, Pectobacterium carotovorum. The hypothesis that in the soft rot, the liberation of starch (not utilized by P. carotovorum) makes this polymer available to Salmonella spp., thus allowing it to colonize soft rots, was tested first and proven null. To identify the functions involved in Salmonella soft rot colonization, we carried out transposon insertion sequencing coupled with the phenotypic characterization of the mutants. The data indicate that Salmonella spp. experience a metabolic shift in response to the changes in the environment brought on by Pectobacterium spp. and likely coordinated by the csrBC small regulatory RNA. While csrBC and flhD appear to be of importance in the soft rot, the global two-component system encoded by barA sirA (which controls csrBC and flhDC under laboratory conditions) does not appear to be necessary for the observed phenotype. Motility and the synthesis of nucleotides and amino acids play critical roles in the growth of Salmonella spp. in the soft rot. IMPORTANCE Outbreaks of produce-associated illness continue to be a food safety concern. Earlier studies demonstrated that the presence of phytopathogens on produce was a significant risk factor associated with increased Salmonella carriage on fruits and vegetables. Here, we genetically characterize some of the requirements for interactions between Salmonella and phytobacteria that allow Salmonella spp. to establish a niche within an alternate host (tomato). Pathways necessary for nucleotide synthesis, amino acid synthesis, and motility are identified as contributors to the persistence of Salmonella spp. in soft rots. PMID:29247060

Control of postharvest soft rot caused by Erwinia carotovora of vegetables by a strain of Bacillus amyloliquefaciens and its potential modes of action.

PubMed

Zhao, Yancun; Li, Pengxia; Huang, Kaihong; Wang, Yuning; Hu, Huali; Sun, Ya

2013-03-01

Erwinia carotovora subsp. carotovora (Ecc), the causal agent of bacterial soft rot, is one of the destructive pathogens of postharvest vegetables. In this study, a bacterial isolate (BGP20) from the vegetable farm soil showed strong antagonistic activity against Ecc in vitro, and its twofold cell-free culture filtrate showed excellent biocontrol effect in controlling the postharvest bacterial soft rot of potatoes at 25 °C. The anti-Ecc metabolites produced by the isolate BGP20 had a high resistance to high temperature, UV-light and protease K. Based on the colonial morphology, cellular morphology, sporulation, and partial nucleotide sequences of 16S rRNA and gyrB gene, the isolate BGP20 was identified as Bacillus amyloliquefaciens subsp. plantarum. Further in vivo assays showed that the BGP20 cell culture was more effective in controlling the postharvest bacterial soft rot of green peppers and Chinese cabbages than its twofold cell-free culture filtrate. In contrast, the biocontrol effect and safety of the BGP20 cell culture were very poor on potatoes. In the wounds of potatoes treated with both the antagonist BGP20 and the pathogen Ecc, the viable count of Ecc was 31,746 times that of BGP20 at 48 h of incubation at 25 °C. But in the wounds of green peppers, the viable count of BGP20 increased 182.3 times within 48 h, and that of Ecc increased only 51.3 %. In addition, the treatment with both BGP20 and Ecc induced higher activity of phenylalanine ammonia-lyase (PAL) than others in potatoes. But the same treatment did not induce an increase of PAL activity in green peppers. In conclusion, the present study demonstrated that the isolate BGP20 is a promising candidate in biological control of postharvest bacterial soft rot of vegetables, but its main mode of action is different among various vegetables.

Salmonella enterica suppresses Pectobacterium carotovorum subsp. carotovorum population and soft rot progression by acidifying the microaerophilic environment.

PubMed

Kwan, Grace; Charkowski, Amy O; Barak, Jeri D

2013-02-12

Although enteric human pathogens are usually studied in the context of their animal hosts, a significant portion of their life cycle occurs on plants. Plant disease alters the phyllosphere, leading to enhanced growth of human pathogens; however, the impact of human pathogens on phytopathogen biology and plant health is largely unknown. To characterize the interaction between human pathogens and phytobacterial pathogens in the phyllosphere, we examined the interactions between Pectobacterium carotovorum subsp. carotovorum and Salmonella enterica or Escherichia coli O157:H7 with regard to bacterial populations, soft rot progression, and changes in local pH. The presence of P. carotovorum subsp. carotovorum enhanced the growth of both S. enterica and E. coli O157:H7 on leaves. However, in a microaerophilic environment, S. enterica reduced P. carotovorum subsp. carotovorum populations and soft rot progression by moderating local environmental pH. Reduced soft rot was not due to S. enterica proteolytic activity. Limitations on P. carotovorum subsp. carotovorum growth, disease progression, and pH elevation were not observed on leaves coinoculated with E. coli O157:H7 or when leaves were coinoculated with S. enterica in an aerobic environment. S. enterica also severely undermined the relationship between the phytobacterial population and disease progression of a P. carotovorum subsp. carotovorum budB mutant defective in the 2,3-butanediol pathway for acid neutralization. Our results show that S. enterica and E. coli O157:H7 interact differently with the enteric phytobacterial pathogen P. carotovorum subsp. carotovorum. S. enterica inhibition of soft rot progression may conceal a rapidly growing human pathogen population. Whereas soft rotted produce can alert consumers to the possibility of food-borne pathogens, healthy-looking produce may entice consumption of contaminated vegetables. Salmonella enterica and Escherichia coli O157:H7 may use plants to move between animal and human hosts. Their populations are higher on plants cocolonized with the common bacterial soft rot pathogen Pectobacterium carotovorum subsp. carotovorum, turning edible plants into a risk factor for human disease. We inoculated leaves with P. carotovorum subsp. carotovorum and S. enterica or E. coli O157:H7 to study the interactions between these bacteria. While P. carotovorum subsp. carotovorum enhanced the growth of both S. enterica and E. coli O157:H7, these human pathogens affected P. carotovorum subsp. carotovorum fundamentally differently. S. enterica reduced P. carotovorum subsp. carotovorum growth and acidified the environment, leading to less soft rot on leaves; E. coli O157:H7 had no such effects. As soft rot signals a food safety risk, the reduction of soft rot symptoms in the presence of S. enterica may lead consumers to eat healthy-looking but S. enterica-contaminated produce.

Pectobacterium polaris sp. nov., isolated from potato (Solanum tuberosum).

PubMed

Dees, Merete Wiken; Lysøe, Erik; Rossmann, Simeon; Perminow, Juliana; Brurberg, May Bente

2017-12-01

The genus Pectobacterium, which belongs to the bacterial family Enterobacteriaceae, contains numerous species that cause soft rot diseases in a wide range of plants. The species Pectobacterium carotovorum is highly heterogeneous, indicating a need for re-evaluation and a better classification of the species. PacBio was used for sequencing of two soft-rot-causing bacterial strains (NIBIO1006 T and NIBIO1392), initially identified as P. carotovorumstrains by fatty acid analysis and sequencing of three housekeeping genes (dnaX, icdA and mdh). Their taxonomic relationship to other Pectobacterium species was determined and the distance from any described species within the genus Pectobacterium was less than 94 % average nucleotide identity (ANI). Based on ANI, phylogenetic data and genome-to-genome distance, strains NIBIO1006 T , NIBIO1392 and NCPPB3395 are suggested to represent a novel species of the genus Pectobacterium, for which the name Pectobacterium polaris sp. nov. is proposed. The type strain is NIBIO1006 T (=DSM 105255 T =NCPPB 4611 T ).

CorA, the magnesium/nickel/cobalt transporter, affects virulence and extracellular enzyme production in the soft rot pathogen Pectobacterium carotovorum.

PubMed

Kersey, Caleb M; Agyemang, Paul A; Dumenyo, C Korsi

2012-01-01

Pectobacterium carotovorum (formerly Erwinia carotovora ssp. carotovora) is a phytopathogenic bacterium that causes soft rot disease, characterized by water-soaked soft decay, resulting from the action of cell wall-degrading exoenzymes secreted by the pathogen. Virulence in soft rot bacteria is regulated by environmental factors, host and bacterial chemical signals, and a network of global and gene-specific bacterial regulators. We isolated a mini-Tn5 mutant of P. carotovorum that is reduced in the production of extracellular pectate lyase, protease, polygalacturonase and cellulase. The mutant is also decreased in virulence as it macerates less host tissues than its parent and is severely impaired in multiplication in planta. The inactivated gene responsible for the reduced virulent phenotype was identified as corA. CorA, a magnesium/nickel/cobalt membrane transporter, is the primary magnesium transporter for many bacteria. Compared with the parent, the CorA(-) mutant is cobalt resistant. The mutant phenotype was confirmed in parental strain P. carotovorum by marker exchange inactivation of corA. A functional corA(+) DNA from P. carotovorum restored exoenzyme production and pathogenicity to the mutants. The P. carotovorum corA(+) clone also restored motility and cobalt sensitivity to a CorA(-) mutant of Salmonella enterica. These data indicate that CorA is required for exoenzyme production and virulence in P. carotovorum. © 2011 THE AUTHORS. MOLECULAR PLANT PATHOLOGY © 2011 BSPP AND BLACKWELL PUBLISHING LTD.

The Salmonella transcriptome in lettuce and cilantro soft rot reveals a niche overlap with the animal host intestine

USDA-ARS?s Scientific Manuscript database

Fresh vegetables have been recurrently associated with salmonellosis outbreaks and Salmonella contamination of retail produce has been correlated positively with the presence of soft rot disease. We observed that Salmonella enterica Typhimurium SL1344 grows to 50-fold greater populations in the pres...

Determining resistance to soft-rot fungi

Treesearch

C. G. Duncan

1965-01-01

A laboratory procedure is outlined that incorporates techniques found to promote soft rot by several fungi. This procedure employs either an agar or a soil substrate. Also presented are the principal findings of experiments underlying the procedure. Results of tests conducted according to the suggested procedure are illustrated. The overall decay resistance of the...

Salmonella enterica Suppresses Pectobacterium carotovorum subsp. carotovorum Population and Soft Rot Progression by Acidifying the Microaerophilic Environment

PubMed Central

Kwan, Grace; Charkowski, Amy O.; Barak, Jeri D.

2013-01-01

ABSTRACT Although enteric human pathogens are usually studied in the context of their animal hosts, a significant portion of their life cycle occurs on plants. Plant disease alters the phyllosphere, leading to enhanced growth of human pathogens; however, the impact of human pathogens on phytopathogen biology and plant health is largely unknown. To characterize the interaction between human pathogens and phytobacterial pathogens in the phyllosphere, we examined the interactions between Pectobacterium carotovorum subsp. carotovorum and Salmonella enterica or Escherichia coli O157:H7 with regard to bacterial populations, soft rot progression, and changes in local pH. The presence of P. carotovorum subsp. carotovorum enhanced the growth of both S. enterica and E. coli O157:H7 on leaves. However, in a microaerophilic environment, S. enterica reduced P. carotovorum subsp. carotovorum populations and soft rot progression by moderating local environmental pH. Reduced soft rot was not due to S. enterica proteolytic activity. Limitations on P. carotovorum subsp. carotovorum growth, disease progression, and pH elevation were not observed on leaves coinoculated with E. coli O157:H7 or when leaves were coinoculated with S. enterica in an aerobic environment. S. enterica also severely undermined the relationship between the phytobacterial population and disease progression of a P. carotovorum subsp. carotovorum budB mutant defective in the 2,3-butanediol pathway for acid neutralization. Our results show that S. enterica and E. coli O157:H7 interact differently with the enteric phytobacterial pathogen P. carotovorum subsp. carotovorum. S. enterica inhibition of soft rot progression may conceal a rapidly growing human pathogen population. Whereas soft rotted produce can alert consumers to the possibility of food-borne pathogens, healthy-looking produce may entice consumption of contaminated vegetables. PMID:23404399

Iron Deficiency Induced by Chrysobactin in Saintpaulia Leaves Inoculated with Erwinia chrysanthemi.

PubMed Central

Neema, C.; Laulhere, J. P.; Expert, D.

1993-01-01

In this communication, we examine the fate of iron during soft rot pathogenesis caused by Erwinia chrysanthemi on its host, Saintpaulia ionantha. The spread of soft rot caused by this enterobacterium was previously shown to depend on a functional genetic locus encoding a high-affinity iron assimilation system involving the catechol-type siderophore chrysobactin. Leaf intercellular fluid from healthy plants was analyzed with regard to the iron content and its availability for bacterial growth. It was compared to the fluid from diseased plants for the presence of strong iron ligands, using a new approach based on the iron-binding property of an ion-exchange resin. Further characterization allowed the identification of chrysobactin in diseased tissues, thus providing the first evidence for the external release of a microbial siderophore during pathogenesis. Competition for nutritional iron was also studied through a plant-bacterial cell system: iron incorporated into plant ferritin appeared to be considerably reduced in bacteria-treated suspension soybean cells. The same effect was visualized during treatment of soybean cells with axenic leaf intercellular fluid from E. chrysanthemi-inoculated saintpaulia leaves or with chrysobactin. PMID:12231882

Enhanced bioprocessing of lignocellulose: Wood-rot fungal saccharification and fermentation of corn fiber to ethanol

NASA Astrophysics Data System (ADS)

Shrestha, Prachand

This research aims at developing a biorefinery platform to convert corn-ethanol coproduct, corn fiber, into fermentable sugars at a lower temperature with minimal use of chemicals. White-rot (Phanerochaete chrysosporium), brown-rot (Gloeophyllum trabeum) and soft-rot (Trichoderma reesei) fungi were used in this research to biologically break down cellulosic and hemicellulosic components of corn fiber into fermentable sugars. Laboratory-scale simultaneous saccharification and fermentation (SSF) process proceeded by in-situ cellulolytic enzyme induction enhanced overall enzymatic hydrolysis of hemi/cellulose from corn fiber into simple sugars (mono-, di-, tri-saccharides). The yeast fermentation of hydrolyzate yielded 7.1, 8.6 and 4.1 g ethanol per 100 g corn fiber when saccharified with the white-, brown-, and soft-rot fungi, respectively. The highest corn-to-ethanol yield (8.6 g ethanol/100 g corn fiber) was equivalent to 42 % of the theoretical ethanol yield from starch and cellulose in corn fiber. Cellulase, xylanase and amylase activities of these fungi were also investigated over a week long solid-substrate fermentation of corn fiber. G. trabeum had the highest activities for starch (160 mg glucose/mg protein.min) and on day three of solid-substrate fermentation. P. chrysosporium had the highest activity for xylan (119 mg xylose/mg protein.min) on day five and carboxymethyl cellulose (35 mg glucose/mg protein.min) on day three of solid-substrate fermentation. T. reesei showed the highest activity for Sigma cell 20 (54.8 mg glucose/mg protein.min) on day 5 of solid-substrate fermentation. The effect of different pretreatments on SSF of corn fiber by fungal processes was examined. Corn fiber was treated at 30 °C for 2 h with alkali [2% NaOH (w/w)], alkaline peroxide [2% NaOH (w/w) and 1% H2O 2 (w/w)], and by steaming at 100 °C for 2 h. Mild pretreatment resulted in improved ethanol yields for brown- and soft-rot SSF, while white-rot and Spezyme CP SSFs showed no improvement in ethanol yields. We showed that saccharification of lignocellulosic material with a wood-rot fungal process is quite feasible. Corn fiber from wet milling was best degraded to sugars using aerobic solid state fermentation with the soft-rot fungus T. reesei. However, it was shown that both the white-rot fungus P. chrysosporium and brown-rot fungus G. trabeum had the ability to produce additional consortia of hemi/cellulose degrading enzymes. It is likely that a consortium of enzymes from these fungi would be the best approach in saccharification of lignocellulose. In all cases, a subsequent anaerobic yeast process under submerged conditions is required to ferment the released sugars to ethanol. To our knowledge, this is the first time report on production of cellulolytic enzymes from wet-milled corn fiber using white- and brown-rot fungi for sequential fermentation of corn fiber hydrolyzate to ethanol. Keywords: lignocellulose, ethanol, biofuel, bioeconomy, biomass, renewable resources, corn fiber, pretreatment, solid-substrate fermentation, simultaneous saccharification and fermentation (SSF), white-rot fungus, brown-rot fungus, soft-rot fungus, fermentable sugars, enzyme activities, cellulytic enzymes Phanerochaete chrysosporium, Gloleophyllum trabeum, Trichoderma reesei, Saccharomyces cerevisiae.

Induction of Rhizopus oryzae germination under starvation using host metabolites increases spore susceptibility to heat stress

USDA-ARS?s Scientific Manuscript database

Sweet potato is a nutritional source worldwide. Soft rot caused by Rhizopus spp. is a major limiting factor in the storage of produce, rendering it potentially unsafe for human consumption. In this study, Rhizopus oryzae was used to develop a concept of postharvest disease control by weakening the p...

Quorum Sensing Signaling Molecules Produced by Reference and Emerging Soft-Rot Bacteria (Dickeya and Pectobacterium spp.)

PubMed Central

Crépin, Alexandre; Barbey, Corinne; Beury-Cirou, Amélie; Hélias, Valérie; Taupin, Laure; Reverchon, Sylvie; Nasser, William; Faure, Denis; Dufour, Alain; Orange, Nicole; Feuilloley, Marc; Heurlier, Karin; Burini, Jean-François; Latour, Xavier

2012-01-01

Background Several small diffusible molecules are involved in bacterial quorum sensing and virulence. The production of autoinducers-1 and -2, quinolone, indole and γ-amino butyrate signaling molecules was investigated in a set of soft-rot bacteria belonging to six Dickeya or Pectobacterium species including recent or emerging potato isolates. Methodology/Principal Findings Using bacterial biosensors, immunoassay, and chromatographic analysis, we showed that soft-rot bacteria have the common ability to produce transiently during their exponential phase of growth the N-3-oxo-hexanoyl- or the N-3-oxo-octanoyl-l-homoserine lactones and a molecule of the autoinducer-2 family. Dickeya spp. produced in addition the indole-3-acetic acid in tryptophan-rich conditions. All these signaling molecules have been identified for the first time in the novel Dickeya solani species. In contrast, quinolone and γ-amino butyrate signals were not identified and the corresponding synthases are not present in the available genomes of soft-rot bacteria. To determine if the variations of signal production according to growth phase could result from expression modifications of the corresponding synthase gene, the respective mRNA levels were estimated by reverse transcriptase-PCR. While the N-acyl-homoserine lactone production is systematically correlated to the synthase expression, that of the autoinducer-2 follows the expression of an enzyme upstream in the activated methyl cycle and providing its precursor, rather than the expression of its own synthase. Conclusions/Significance Despite sharing the S-adenosylmethionine precursor, no strong link was detected between the production kinetics or metabolic pathways of autoinducers-1 and -2. In contrast, the signaling pathway of autoinducer-2 seems to be switched off by the indole-3-acetic acid pathway under tryptophan control. It therefore appears that the two genera of soft-rot bacteria have similarities but also differences in the mechanisms of communication via the diffusible molecules. Our results designate autoinducer-1 lactones as the main targets for a global biocontrol of soft-rot bacteria communications, including those of emerging isolates. PMID:22539957

The Salmonella Transcriptome in Lettuce and Cilantro Soft Rot Reveals a Niche Overlap with the Animal Host Intestine

PubMed Central

Goudeau, Danielle M.; Parker, Craig T.; Zhou, Yaguang; Sela, Shlomo; Kroupitski, Yulia

2013-01-01

Fresh vegetables have been recurrently associated with salmonellosis outbreaks, and Salmonella contamination of retail produce has been correlated positively with the presence of soft rot disease. We observed that population sizes of Salmonella enterica serovar Typhimurium SL1344 increased 56-fold when inoculated alone onto cilantro leaves, versus 2,884-fold when coinoculated with Dickeya dadantii, a prevalent pathogen that macerates plant tissue. A similar trend in S. enterica populations was observed for soft-rotted lettuce leaves. Transcriptome analysis of S. enterica cells that colonized D. dadantii-infected lettuce and cilantro leaves revealed a clear shift toward anaerobic metabolism and catabolism of substrates that are available due to the degradation of plant cells by the pectinolytic pathogen. Twenty-nine percent of the genes that were upregulated in cilantro macerates were also previously observed to have increased expression levels in the chicken intestine. Furthermore, multiple genes induced in soft rot lesions are also involved in the colonization of mouse, pig, and bovine models of host infection. Among those genes, the operons for ethanolamine and propanediol utilization as well as for the synthesis of cobalamin, a cofactor in these pathways, were the most highly upregulated genes in lettuce and cilantro lesions. In S. Typhimurium strain LT2, population sizes of mutants deficient in propanediol utilization or cobalamin synthesis were 10- and 3-fold lower, respectively, than those of the wild-type strain in macerated cilantro (P < 0.0002); in strain SL1344, such mutants behaved similarly to the parental strain. Anaerobic conditions and the utilization of nutrients in macerated plant tissue that are also present in the animal intestine indicate a niche overlap that may explain the high level of adaptation of S. enterica to soft rot lesions, a common postharvest plant disease. PMID:23104408

Identification of Fusarium species isolated from stored apple fruit in Croatia.

PubMed

Sever, Zdravka; Ivić, Dario; Kos, Tomislav; Miličević, Tihomir

2012-12-01

Several species of the genus Fusarium can cause apple fruit to rot while stored. Since Fusarium taxonomy is very complex and has constantly been revised and updated over the last years, the aim of this study was to identify Fusarium species from rotten apples, based on combined morphological characteristics and molecular data. We identified 32 Fusarium isolates from rotten apple fruit of cultivars Golden Delicious, Jonagold, Idared, and Pink Lady, stored in Ultra Low Oxygen (ULO) conditions. Fusarium rot was detected in 9.4 % to 33.2 % of naturally infected apples, depending on the cultivar. The symptoms were similar in all four cultivars: a soft circular brown necrosis of different extent, with or without visible sporulation. Fusarium species were identified by the morphology of cultures grown on potato-dextrose agar (PDA) and carnation leaf agar (CLA). Twenty one isolates were identified as Fusarium avenaceum and confirmed as such with polymerase chain reaction (PCR) using specific primer pair FA-ITSF and FA-ITSR. F. pseudograminearum,F. semitectum, F. crookwellense, and F. compactum were identified by morphological characteristics. F.avenaceum can produce several mycotoxins and its dominance in Fusarium rot points to the risk of mycotoxin contamination of apple fruit juices and other products for human consumption. Pathogenicity tests showed typical symptoms of Fusarium rot in most of the inoculated wounded apple fruits. In this respect Fusarium avenaceum, as the dominant cause of Fusarium rot in stored apple fruits is a typical wound parasite.

Biocontrol of the Potato Blackleg and Soft Rot Diseases Caused by Dickeya dianthicola.

PubMed

Raoul des Essarts, Yannick; Cigna, Jérémy; Quêtu-Laurent, Angélique; Caron, Aline; Munier, Euphrasie; Beury-Cirou, Amélie; Hélias, Valérie; Faure, Denis

2016-01-01

Development of protection tools targeting Dickeya species is an important issue in the potato production. Here, we present the identification and the characterization of novel biocontrol agents. Successive screenings of 10,000 bacterial isolates led us to retain 58 strains that exhibited growth inhibition properties against several Dickeya sp. and/or Pectobacterium sp. pathogens. Most of them belonged to the Pseudomonas and Bacillus genera. In vitro assays revealed a fitness decrease of the tested Dickeya sp. and Pectobacterium sp. pathogens in the presence of the biocontrol agents. In addition, four independent greenhouse assays performed to evaluate the biocontrol bacteria effect on potato plants artificially contaminated with Dickeya dianthicola revealed that a mix of three biocontrol agents, namely, Pseudomonas putida PA14H7 and Pseudomonas fluorescens PA3G8 and PA4C2, repeatedly decreased the severity of blackleg symptoms as well as the transmission of D. dianthicola to the tuber progeny. This work highlights the use of a combination of biocontrol strains as a potential strategy to limit the soft rot and blackleg diseases caused by D. dianthicola on potato plants and tubers. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Biocontrol of the Potato Blackleg and Soft Rot Diseases Caused by Dickeya dianthicola

PubMed Central

Raoul des Essarts, Yannick; Cigna, Jérémy; Quêtu-Laurent, Angélique; Caron, Aline; Munier, Euphrasie; Beury-Cirou, Amélie

2015-01-01

Development of protection tools targeting Dickeya species is an important issue in the potato production. Here, we present the identification and the characterization of novel biocontrol agents. Successive screenings of 10,000 bacterial isolates led us to retain 58 strains that exhibited growth inhibition properties against several Dickeya sp. and/or Pectobacterium sp. pathogens. Most of them belonged to the Pseudomonas and Bacillus genera. In vitro assays revealed a fitness decrease of the tested Dickeya sp. and Pectobacterium sp. pathogens in the presence of the biocontrol agents. In addition, four independent greenhouse assays performed to evaluate the biocontrol bacteria effect on potato plants artificially contaminated with Dickeya dianthicola revealed that a mix of three biocontrol agents, namely, Pseudomonas putida PA14H7 and Pseudomonas fluorescens PA3G8 and PA4C2, repeatedly decreased the severity of blackleg symptoms as well as the transmission of D. dianthicola to the tuber progeny. This work highlights the use of a combination of biocontrol strains as a potential strategy to limit the soft rot and blackleg diseases caused by D. dianthicola on potato plants and tubers. PMID:26497457

Isolation, characterization, and evaluation of multi-trait plant growth promoting rhizobacteria for their growth promoting and disease suppressing effects on ginger.

PubMed

Dinesh, Raghavan; Anandaraj, Muthuswamy; Kumar, Aundy; Bini, Yogiyar Kundil; Subila, Kizhakke Purayil; Aravind, Ravindran

2015-04-01

In this study, 100 PGPR strains isolated from different varieties of ginger (Zingiber officinale Rosc.) were first characterized for their morphological, biochemical, and nutrient mobilization traits in vitro. The PGPR were also screened in vitro for inhibition of Pythium myriotylum causing soft rot in ginger. Results revealed that only five PGPR showed >70% suppression of P. myriotylum. These 5 PGPR viz., GRB (Ginger rhizobacteria) 25--Burkholderia cepacia, GRB35--Bacillus amyloliquefaciens; GRB58--Serratia marcescens; GRB68--S. marcescens; GRB91--Pseudomonas aeruginosa were used for further growth promotion and biocontrol studies in the green house and field. The green house study revealed that GRB35 (B. amyloliquefaciens) and GRB68 (S. marcescens) registered markedly higher sprouting (96.3%) and lower disease incidence (48.1%) and greater rhizome yield (365.6 g pot(-1) and 384.4 g pot(-1), respectively), while control registered the lowest sprouting (66%), maximum soft rot incidence (100%) and lowest rhizome yield (134.4 g pot(-1)). In the field experiments also, GRB68 (S. marcescens) and GRB35 (B. amyloliquefaciens) registered the greatest sprouting (80% each), markedly lower soft rot incidence (5.2% and 7.3%, respectively) and higher yield (5.0 and 4.3 kg(3)m(-2), respectively) compared to chemicals like Streptomycin sulphate (73.0%, 18.5% and 2.3 kg(3)m(-2), respectively), Metalaxyl-Mancozeb (73.0%, 14.0% and 3.8 kg(3)m(-2), respectively) and control (73.0%, 25.1% and 2.2 kg 3m(-2), respectively). Overall, the results suggested that for growth promotion and management of soft rot disease in ginger, GRB35 B. amyloliquefaciens and GRB68 S. marcescens could be good alternatives to chemical measures. Since, the latter has been reported to be an opportunistic human pathogen, we recommend the use of B. amyloliquefaciens for integration into nutrient and disease management schedules for ginger cultivation. Copyright © 2015 Elsevier GmbH. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hutton, D.

The reasons for preservative treatment of cooling tower wood are reviewed along with a summary of which types of treatment are available, how they are applied, and a comparison of materials and processes. Industries often specify minimum quality preservatives for their cooling towers without understanding the loss of strength caused by decay and the economic losses due to a cooling tower failure and lost production. Wood is subject to both chemical (surface delignification and iron rot) and biological (soft rot) attack. A successful preservative treatment that protects against both must have retention and penetration qualities. Research efforts are examining themore » toxicity and environmental impacts of preservatives and exploring the possibility of chemically modifying wood. (DCK)« less

Derivation of Mutants of Erwinia carotovora subsp. betavasculorum Deficient in Export of Pectolytic Enzymes with Potential for Biological Control of Potato Soft Rot

PubMed Central

Costa, José M.; Loper, Joyce E.

1994-01-01

Erwinia carotovora subsp. betavasculorum Ecb168 produces an antibiotic(s) that suppresses growth of the related bacterium Erwinia carotovora subsp. carotovora in culture and in wounds of potato tubers. Strain Ecb168 also produces and secretes pectolytic enzymes and causes a vascular necrosis and root rot of sugar beet. Genes (out) involved in secretion of pectolytic enzymes by Ecb168 were localized to two HindIII fragments (8.5 and 10.5 kb) of Ecb168 genomic DNA by hybridization to the cloned out region of E. carotovora subsp. carotovora and by complementation of Out- mutants of E. carotovora subsp. carotovora. Out- mutants of Ecb168, which did not secrete pectate lyase into the culture medium, were obtained when deletions internal to either HindIII fragment were introduced into the genome of Ecb168 through marker exchange mutagenesis. Out- mutants of Ecb168 were complemented to the Out+ phenotype by introduction of the corresponding cloned HindIII fragment. Out- mutants of Ecb168 were less virulent than the Out+ parental strain on potato tubers. Strain Ecb168 and Out- derivatives inhibited the growth of E. carotovora subsp. carotovora in culture, indicating that the uncharacterized antibiotic(s) responsible for antagonism was exported through an out-independent mechanism. Strain Ecb168 and Out- derivatives reduced the establishment of large populations of E. carotovora subsp. carotovora in wounds of potato tubers and suppressed tuber soft rot caused by E. carotovora subsp. carotovora. PMID:16349316

A bionanohybrid ZnAl-NADS ecological pesticide as a treatment for soft rot disease in potato (Solanum tuberosum L.).

PubMed

Morales-Irigoyen, Erika Elizabeth; de Las Mercedes Gómez-Y-Gómez, Yolanda; Flores-Moreno, Jorge Luis; Franco-Hernández, Marina Olivia

2017-09-18

Pectobacterium carotovorum (Pc) is a phytopathogenic strain that causes soft rot disease in potato (Solanum tuberosum L.), resulting in postharvest losses. Chemical control is effective for managing this disease, but overdoses cause adverse effects. Because farmers insist on using chemical agents for crop protection, it is necessary to develop more effective pesticides in which the active compound released can be regulated. In this context, we proposed the synthesis of ZnAl-NADS, in which nalidixic acid sodium salt (NADS) is linked to a ZnAl-NO 3 layered double hydroxide (LDH) host as a nanocarrier. XRD, FT-IR, and SEM analyses confirmed the successful intercalation of NADS into the interplanar LDH space. The drug release profile indicated that the maximum release was completed in 70 or 170 min for free NADS (alone) or for NADS released from ZnAl-NADS, respectively. This slow release was attributed to strong electrostatic interactions between the drug and the anion exchanger. A modulated release is preferable to the action of the bulk NADS, showing increased effectiveness and minimizing the amount of the chemical available to pollute the soil and the water. The fitting data from modified Freundlich and parabolic diffusion models explain the release behavior of the NADS, suggesting that the drug released from ZnAl-NADS bionanohybrid was carried out from the interlamellar sites, according to the ion exchange diffusion process also involving intraparticle diffusion (coeffect). ZnAl-NADS was tested in vitro against Escherichia coli (Ec) and Pc and exhibited bacteriostatic and biocidal effects at 0.025 and 0.075 mg mL -1 , respectively. ZnAl-NADS was also tested in vivo as an ecological pesticide for combating potato soft rot and was found to delay typical disease symptoms. In conclusion, ZnAl-NADS can potentially be used to control pests, infestation, and plant disease.

Attenuation of Quorum Sensing Regulated Virulence of Pectobacterium carotovorum subsp. carotovorum through an AHL Lactonase Produced by Lysinibacillus sp. Gs50

PubMed Central

Garge, Sneha S.; Nerurkar, Anuradha S.

2016-01-01

Quorum sensing (QS) is a mechanism in which Gram negative bacterial pathogens sense their population density through acyl homoserine lactones (AHLs) and regulate the expression of virulence factors. Enzymatic degradation of AHLs by lactonases, known as quorum quenching (QQ), is thus a potential strategy for attenuating QS regulated bacterial infections. We characterised the QQ activity of soil isolate Lysinibacillus sp. Gs50 and explored its potential for controlling bacterial soft rot of crop plants. Lysinibacillus sp. Gs50 inactivated AHL, which could be restored upon acidification, suggested that inactivation was due to the lactone ring hydrolysis of AHL. Heterologous expression of cloned gene for putative hydrolase (792 bp) designated adeH from Lysinibacillus sp. Gs50 produced a ~29 kDa protein which degraded AHLs of varying chain length. Mass spectrometry analysis of AdeH enzymatic reaction product revealed that AdeH hydrolyses the lactone ring of AHL and hence is an AHL lactonase. Multiple sequence alignment of the amino acid sequence of AdeH showed that it belongs to the metallo- β- lactamase superfamily, has a conserved “HXHXDH” motif typical of AHL lactonases. KM for AdeH for C6HSL was found to be 3.089 μM and the specific activity was 0.8 picomol min-1μg-1. AdeH has not so far been reported from any Lysinibacillus sp. and has less than 40% identity with known AHL lactonases. Finally we found that Lysinibacillus sp. Gs50 can degrade AHL produced by Pectobacterium carotovorum subsp. carotovorum (Pcc), a common cause of soft rot. This QQ activity causes a decrease in production of plant cell wall degrading enzymes of Pcc and attenuates symptoms of soft rot in experimental infection of potato, carrot and cucumber. Our results demonstrate the potential of Lysinibacillus sp. Gs50 as a preventive and curative biocontrol agent. PMID:27911925

Imaging mass spectrometry and genome mining reveal highly antifungal virulence factor of mushroom soft rot pathogen.

PubMed

Graupner, Katharina; Scherlach, Kirstin; Bretschneider, Tom; Lackner, Gerald; Roth, Martin; Gross, Harald; Hertweck, Christian

2012-12-21

Caught in the act: imaging mass spectrometry of a button mushroom infected with the soft rot pathogen Janthinobacterium agaricidamnosum in conjunction with genome mining revealed jagaricin as a highly antifungal virulence factor that is not produced under standard cultivation conditions. The structure of jagaricin was rigorously elucidated by a combination of physicochemical analyses, chemical derivatization, and bioinformatics. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The type III secreted effector DspE is required early in Solanum tuberosum leaf infection by Pectobacterium carotovorum to elicit cell death, and requires Wx(3-6)D/E motifs

USDA-ARS?s Scientific Manuscript database

Pectobacterium species are enterobacterial plant-pathogens that cause soft rot disease in diverse plant species. Unlike hemi-biotrophic plant pathogenic bacteria, the type III secretion system (T3SS) of Pectobacterium carotovorum subsp. carotovorum (P. carotovorum) appears to secrete only one effect...

Draft Genome Sequences of New Genomospecies "Candidatus Pectobacterium maceratum" Strains, Which Cause Soft Rot in Plants.

PubMed

Shirshikov, Fedor V; Korzhenkov, Aleksei A; Miroshnikov, Kirill K; Kabanova, Anastasia P; Barannik, Alla P; Ignatov, Alexander N; Miroshnikov, Konstantin A

2018-04-12

Investigation of collections of phytopathogenic bacteria has revealed some strains distinct from known Pectobacterium spp. We report here the draft genome sequences of five such strains, isolated during the period of 1947 to 2012. Based on comparative genomics, we propose a new candidate genomospecies of the genus Pectobacterium , " Candidatus Pectobacterium maceratum." Copyright © 2018 Shirshikov et al.

Draft Genome Sequences of New Genomospecies “Candidatus Pectobacterium maceratum” Strains, Which Cause Soft Rot in Plants

PubMed Central

2018-01-01

ABSTRACT Investigation of collections of phytopathogenic bacteria has revealed some strains distinct from known Pectobacterium spp. We report here the draft genome sequences of five such strains, isolated during the period of 1947 to 2012. Based on comparative genomics, we propose a new candidate genomospecies of the genus Pectobacterium, “Candidatus Pectobacterium maceratum.” PMID:29650577

Patterns of lignin degradation and oxidative enzyme secretion by different wood- and litter-colonizing basidiomycetes and ascomycetes grown on beech-wood.

PubMed

Liers, Christiane; Arnstadt, Tobias; Ullrich, René; Hofrichter, Martin

2011-10-01

The degradation of lignocellulose and the secretion of extracellular oxidoreductases were investigated in beech-wood (Fagus sylvatica) microcosms using 11 representative fungi of four different ecophysiological and taxonomic groups causing: (1) classic white rot of wood (e.g. Phlebia radiata), (2) 'nonspecific' wood rot (e.g. Agrocybe aegerita), (3) white rot of leaf litter (Stropharia rugosoannulata) or (4) soft rot of wood (e.g. Xylaria polymorpha). All strong white rotters produced manganese-oxidizing peroxidases as the key enzymes of ligninolysis (75-2200 mU g(-1)), whereas lignin peroxidase activity was not detectable in the wood extracts. Interestingly, activities of two recently discovered peroxidases - aromatic peroxygenase and a manganese-independent peroxidase of the DyP-type - were detected in the culture extracts of A. aegerita (up to 125 mU g(-1)) and Auricularia auricula-judae (up to 400 mU g(-1)), respectively. The activity of classic peroxidases correlated to some extent with the removal of wood components (e.g. Klason lignin) and the release of small water-soluble fragments (0.5-1.0 kDa) characterized by aromatic constituents. In contrast, laccase activity correlated with the formation of high-molecular mass fragments (30-200 kDa). The differences observed in the degradation patterns allow to distinguish the rot types caused by basidiomycetes and ascomycetes and may be suitable for following the effects of oxidative key enzymes (ligninolytic peroxidases vs. laccases, role of novel peroxidases) during wood decay. © 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

Carbohydrate and ethane release with Erwinia carotovora subspecies betavasculorum--induced necrosis.

PubMed

Kuykendall, L David; Hunter, William J

2008-02-01

Erwinia carotovora subspecies betavasculorum, also known as E. betavasculorum and Pectobacterium betavasculorum, is a soil bacterium that has the capacity to cause root rot necrosis of sugarbeets. The qualitatively different pathogenicity exhibited by the virulent E. carotovora strain and two avirulent strains, a Citrobacter sp. and an Enterobacter cloacae, was examined using digital analysis of photographic evidence of necrosis as well as for carbohydrate, ethane, and ethylene release compared with uninoculated potato tuber slices. Visual scoring of necrosis was superior to digital analysis of photographs. The release of carbohydrates and ethane from potato tuber slices inoculated with the soft rot necrosis-causing Erwinia was significantly greater than that of potato tuber slices that had not been inoculated or that had been inoculated with the nonpathogenic E. cloacae and Citrobacter sp. strains. Interestingly, ethylene production from potato slices left uninoculated or inoculated with the nonpathogenic Citrobacter strain was 5- to 10-fold higher than with potato slices inoculated with the pathogenic Erwinia strain. These findings suggest that (1) carbohydrate release might be a useful measure of the degree of pathogenesis, or relative virulence; and that (2) bacterial suppression of ethylene formation may be a critical step in root rot disease formation.

Effect of Preservative Pretreatment on the Biological Durability of Corn Straw Fiber/HDPE Composites.

PubMed

Xuan, Lihui; Hui, Dongxue; Cheng, Wanli; Wong, Andrew H H; Han, Guangping; Tan, Wei Khong; Tawi, Carlson A D

2017-07-12

The effects of alkaline copper quaternary (ACQ) and zinc borate (ZB) on the resistance of corn stalk fiber (CSF)-reinforced high-density polyethylene (HDPE) composites to biodegradation were examined. Both biocides could inhibit termites, mold fungi, and wood-decay fungi, even at high CSF formulations (i.e., 60%). Additionally, ACQ enhanced the resistance of the composite materials to certain biotic stresses better than ZB. The CSF/HDPE composites treated with ACQ at the 3.0% level exhibited a superior performance against termites, white rot fungi, and brown rot fungi. ACQ treatment at the 1% level was optimal for inhibiting soft rot fungi. Furthermore, mold growth was not observed on ACQ-treated CSF/HDPE samples. The untreated CSF/HDPE composites were more susceptible to mold infections and decay than the untreated poplar/HDPE composites, likely because of an incomplete removal of the pith. The chemical features of the corn stalk may also have influenced these differences, but this possibility will need to be explored in future investigations. Furthermore, the CSF component of CSF/HDPE composites is highly susceptible to fungal attacks, with the soft rot fungus inducing the largest mass losses, followed by the white rot fungus, and then the brown rot fungus.

Effect of Preservative Pretreatment on the Biological Durability of Corn Straw Fiber/HDPE Composites

PubMed Central

Xuan, Lihui; Hui, Dongxue; Cheng, Wanli; Wong, Andrew H. H.; Han, Guangping; Tan, Wei Khong; Tawi, Carlson A. D.

2017-01-01

The effects of alkaline copper quaternary (ACQ) and zinc borate (ZB) on the resistance of corn stalk fiber (CSF)-reinforced high-density polyethylene (HDPE) composites to biodegradation were examined. Both biocides could inhibit termites, mold fungi, and wood-decay fungi, even at high CSF formulations (i.e., 60%). Additionally, ACQ enhanced the resistance of the composite materials to certain biotic stresses better than ZB. The CSF/HDPE composites treated with ACQ at the 3.0% level exhibited a superior performance against termites, white rot fungi, and brown rot fungi. ACQ treatment at the 1% level was optimal for inhibiting soft rot fungi. Furthermore, mold growth was not observed on ACQ-treated CSF/HDPE samples. The untreated CSF/HDPE composites were more susceptible to mold infections and decay than the untreated poplar/HDPE composites, likely because of an incomplete removal of the pith. The chemical features of the corn stalk may also have influenced these differences, but this possibility will need to be explored in future investigations. Furthermore, the CSF component of CSF/HDPE composites is highly susceptible to fungal attacks, with the soft rot fungus inducing the largest mass losses, followed by the white rot fungus, and then the brown rot fungus. PMID:28773150

Fungal Disfigurement of Paper, and Soft Rot of Cedar Shingles 1

PubMed Central

Eveleigh, D. E.

1970-01-01

Disfiguration of paper by Cladosporium cladosporioides is described, and the association between “soft rot” fungi and the greying of cedar shingles in marine locations is reported. Images PMID:5463581

7 CFR 51.1913 - Serious damage.

Code of Federal Regulations, 2013 CFR

2013-01-01

...) Soft ripe tomatoes or tomatoes affected by the soft rot. (b) Fresh holes or cuts, or any holes or cuts... adjacent to the stem scar and more than 1/4 inch in diameter. (h) Fruit actually infested with worms. ...

7 CFR 51.1913 - Serious damage.

Code of Federal Regulations, 2014 CFR

2014-01-01

...) Soft ripe tomatoes or tomatoes affected by the soft rot. (b) Fresh holes or cuts, or any holes or cuts... adjacent to the stem scar and more than 1/4 inch in diameter. (h) Fruit actually infested with worms. ...

The rotation-powered nature of some soft gamma-ray repeaters and anomalous X-ray pulsars

NASA Astrophysics Data System (ADS)

Coelho, Jaziel G.; Cáceres, D. L.; de Lima, R. C. R.; Malheiro, M.; Rueda, J. A.; Ruffini, R.

2017-03-01

Context. Soft gamma-ray repeaters (SGRs) and anomalous X-ray pulsars (AXPs) are slow rotating isolated pulsars whose energy reservoir is still matter of debate. Adopting neutron star (NS) fiducial parameters; mass M = 1.4 M⊙, radius R = 10 km, and moment of inertia, I = 1045 g cm2, the rotational energy loss, Ėrot, is lower than the observed luminosity (dominated by the X-rays) LX for many of the sources. Aims: We investigate the possibility that some members of this family could be canonical rotation-powered pulsars using realistic NS structure parameters instead of fiducial values. Methods: We compute the NS mass, radius, moment of inertia and angular momentum from numerical integration of the axisymmetric general relativistic equations of equilibrium. We then compute the entire range of allowed values of the rotational energy loss, Ėrot, for the observed values of rotation period P and spin-down rate Ṗ. We also estimate the surface magnetic field using a general relativistic model of a rotating magnetic dipole. Results: We show that realistic NS parameters lowers the estimated value of the magnetic field and radiation efficiency, LX/Ėrot, with respect to estimates based on fiducial NS parameters. We show that nine SGRs/AXPs can be described as canonical pulsars driven by the NS rotational energy, for LX computed in the soft (2-10 keV) X-ray band. We compute the range of NS masses for which LX/Ėrot< 1. We discuss the observed hard X-ray emission in three sources of the group of nine potentially rotation-powered NSs. This additional hard X-ray component dominates over the soft one leading to LX/Ėrot > 1 in two of them. Conclusions: We show that 9 SGRs/AXPs can be rotation-powered NSs if we analyze their X-ray luminosity in the soft 2-10 keV band. Interestingly, four of them show radio emission and six have been associated with supernova remnants (including Swift J1834.9-0846 the first SGR observed with a surrounding wind nebula). These observations give additional support to our results of a natural explanation of these sources in terms of ordinary pulsars. Including the hard X-ray emission observed in three sources of the group of potential rotation-powered NSs, this number of sources with LX/Ėrot< 1 becomes seven. It remains open to verification 1) the accuracy of the estimated distances and 2) the possible contribution of the associated supernova remnants to the hard X-ray emission.

Root rots

Treesearch

Kathryn Robbins; Philip M. Wargo

1989-01-01

Root rots of central hardwoods are diseases caused by fungi that infect and decay woody roots and sometimes also invade the butt portion of the tree. By killing and decaying roots, root rotting fungi reduce growth, decrease tree vigor, and cause windthrow and death. The most common root diseases of central hardwoods are Armillaria root rot, lnonotus root rot, and...

Response of the Andean diversity panel to root rot in a root rot nursery in Puerto Rico

USDA-ARS?s Scientific Manuscript database

The Andean Diversity Panel (ADP) was evaluated under low-fertility and root rot conditions in two trials conducted in 2013 and 2015 in Isabela, Puerto Rico. About 246 ADP lines were evaluated in the root rot nursery with root rot and stem diseases caused predominantly by Fusarium solani, which cause...

First report of Fusarium proliferatum causing dry rot in Michigan commercial potato (Solanum tuberosum) production

USDA-ARS?s Scientific Manuscript database

Fusarium dry rot of potato is a postharvest disease caused by several Fusarium spp. and is of worldwide importance. Thirteen Fusarium spp. have been implicated in fungal dry rots of potatoes worldwide. Among them, 11 species have been reported causing potato dry rot of seed tubers in the northern Un...

Evidence from Serpula lacrymans that 2,5-Dimethoxyhydroquinone Is a Lignocellulolytic Agent of Divergent Brown Rot Basidiomycetes

Treesearch

Premsagar Korripally; Vitaliy I. Timokhin; Carl J. Houtman; Michael D. Mozuch; Kenneth E. Hammel

2013-01-01

Basidiomycetes that cause brown rot of wood are essential biomass recyclers in coniferous forest ecosystems and a major cause of failure in wooden structures. Recent work indicates that distinct lineages of brown rot fungi have arisen independently from ligninolytic white rot ancestors via loss of lignocellulolytic enzymes. Brown rot thus proceeds without significant...

Persistence of Gliocephalotrichum spp. causing fruit rot of rambutan (Nephelium lappaceum L.) in Puerto Rico

USDA-ARS?s Scientific Manuscript database

Worldwide, fruit rot of rambutan is an important problem that limits the storage, marketing and long-distance transportation of the fruit. A complex of pathogens has been reported to cause fruit rot of rambutan and significant post-harvest economic losses. During 2009 and 2011 rambutan fruit rot was...

Red Rot of Ponderosa Pine (FIDL)

Treesearch

Stuart R. Andrews

1971-01-01

Red rot caused by the fungus Polyporus anceps Peck is the most important heart rot of ponderosa pine (Pinus ponderosa Laws.) in the Southwest (in Arizona and New Mexico), the Black Hills of South Dakota, and some localities in Colorado, Montana, and Idaho. It causes only insignificant losses to this species elsewhere in the West. The red rot fungus rarely attacks other...

Wood digestion in Pselactus spadix Herbst--a weevil attacking marine timber structures.

PubMed

Oevering, Pascal; Pitman, Andrew J; Pandey, Krishna K

2003-04-01

Pselactus spadix tunnels timber structures in the marine environment. Recent studies reported a cosmopolitan distribution for this weevil, which is frequently found in harbour and port areas. P. spadix feeds on timber (hardwood and softwood) in immature and adult life stages, but its digestion of wood components had not been investigated. Using dry weight analyses of tunnel walls and frass produced, P. spadix adults consumed Scots pine with soft rot decay at a rate of 1.59 +/- 0.37 mg d-1 and the digestibility of this substrate was 57.96 +/- 5.89 (i.e. for 100 mg consumed SR-pine, 58 mg was digested). Using gravimetric analysis to quantify structural wood components in tunnel walls and frass, P. spadix adults were found to digest cellulose, lignin and hemicellulose with digestibility coefficients of 82.2, 41.2 and 14.5 respectively. Fourier Transform Infrared (FTIR) spectroscopy analyses of tunnel walls and frass of adults and larvae from soft rotted pine also indicated digestion of all structural components, with larvae digesting cellulose and lignin more efficiently than adults. When FTIR was employed to analyse adult tunnel walls and frass from undecayed pine, cellulose and hemicellulose were digested, but no evidence of lignin digestion was found. This study shows that adults digest lignin when soft rot is present and suggests a symbiotic function of wood degrading microorganisms.

Fungicides reduce Rhododendron root rot and mortality caused by Phytophthora cinnamomi, but not by P. plurivora

USDA-ARS?s Scientific Manuscript database

Rhododendron root rot, caused by several Phytophthora species, can cause devastating losses in nursery-grown plants. Most research on chemical control of root rot has focused on Phytophthora cinnamomi. However, it is unknown whether treatments recommended for P. cinnamomi are also effective for othe...

Systems approach-based mitigation of postharvest diseases to overcome trade barriers for Washington apples

USDA-ARS?s Scientific Manuscript database

Speck rot caused by Phacidiopycnis washingtonensis and Sphaeropsis rot caused by S. pyriputrescens were reported as new postharvest fruit rot diseases in Washington State in the mid-2000s. Both diseases can cause significant postharvest losses of fruit if left uncontrolled, and the two fungi have be...

Janthinobacterium agaricidamnosum sp. nov., a soft rot pathogen of Agaricus bisporus.

PubMed

Lincoln, S P; Fermor, T R; Tindall, B J

1999-10-01

A novel bacterium has been found that causes a soft rot disease of Agaricus bisporus, the cultivated mushroom. It has been characterized using nutritional, physiological, chemical and molecular techniques. Based on these data, it was shown to have many characteristics in common with members of the genus Janthinobacterium. Despite similarities to the only described species within this genus, Janthinobacterium lividum, there were a number of differences between the mushroom pathogen isolated and this species. Despite the high degree of genotypic similarity between members of the genus Janthinobacterium and Herbaspirillum, as evidenced by DNA-RNA hybridization, and the high degree of 16S rDNA sequence similarity between members of the genera Janthinobacterium, Herbaspirillum, Oxalobacter and Duganella, as well as the generically misnamed Pseudomonas lemoignei, it was possible to show that members of the genus Janthinobacterium could be easily distinguished from these taxa. The data also indicated that the mushroom pathogenic strains represent a novel species within the genus Janthinobacterium for which the name Janthinobacterium agaricidamnosum sp. nov. is proposed. The type strain of this species has been deposited in the Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH, Braunschweig, Germany, as DSM 9628T and at the National Collection of Plant-pathogenic bacteria, UK, as NCPPB 3945T. To aid practical control of the disease, the effect of the relative humidity on symptom expression on Agaricus bisporus was determined.

First report of brown rot on apple fruit caused by Monilinia fructicola in the United States

USDA-ARS?s Scientific Manuscript database

Brown rot, caused by Monilinia fructicola (G. Wint.) Honey, is the most devastating disease of stone fruits in North America resulting in significant economic losses. The fungus has been recently reported to cause pre and postharvest brown rot on apple fruit in Germany, Italy, and Serbia. However, M...

7 CFR 51.1901 - U.S. Grade A.

Code of Federal Regulations, 2011 CFR

2011-01-01

... are not overripe or soft which are well developed, at least fairly well formed, fairly smooth, free..., sunburn, puffiness, catfaces, growth cracks, scars, dry rot, other diseases, insects, hail, or mechanical...

Management of Rhizoctonia root and crown rot of subarbeet

USDA-ARS?s Scientific Manuscript database

Rhizoctonia root and crown rot is caused by the fungus Rhizoctonia solani and is one of the most severe soil-borne diseases of sugarbeet in Minnesota and North Dakota. Rhizoctonia root and crown rot may reduce yield significantly, and diseased beets may cause problems in storage piles. Fields with...

Organic neem compounds inhibit soft-rot fungal growth and improve the strength of anthracite bricks bound with collagen and lignin for use in iron foundry cupolas.

PubMed

Kelsey, D J; Nieto-Delgado, C; Cannon, F S; Brennan, R A

2015-07-01

To examine organic neem compounds for their effective growth inhibition of saprotrophic soft-rot fungi on anthracite bricks bound with collagen and lignin for use in iron foundry cupolas as an alternative fuel source. Azadirachtin, crude neem oil (NO), and clarified neem oil extract (CNO) were combined with copper to inhibit the growth of the soft-rot fungus, Chaetomium globosum. A synergistic interaction was observed between CNO and a low dose of copper on nutrient media (two-factor anova with triplicate replication: P < 0·05). Interaction was confirmed on lab-scale collagen-lignin-anthracite briquettes by measuring their unconfined compressive (UC) strength. The effective collagen strength of the briquettes was enhanced by applying CNO to their surface prior to inoculation: the room temperature UC strength of the briquettes was 28 ± 4·6% greater when CNO (0·4 mg cm(-2) ) was surface-applied, and was 43 ± 3·0% greater when CNO plus copper (0·14 μg cm(-2) ) were surface-applied. Surface application of CNO and copper synergistically prevents fungal growth on bindered anthracite briquettes and increases their room temperature strength. This novel organic fungicidal treatment may increase the storage and performance of anthracite bricks in iron foundries, thereby saving 15-20% of the energy used in conventional coke production. © 2015 The Society for Applied Microbiology.

First report of lily root rot caused by Thantephorus cucumeris AG 2-1 in the United States

USDA-ARS?s Scientific Manuscript database

A disease survey was undertaken in April, 2016 to profile the soilborne fungal pathogens causing root rot and lesions on lily (Lilium longiflorum) cv. Nellie White in Brookings, Oregon, Curry County. Diseased root samples were either blackened or rotted. Several fungal isolates were cultured from in...

Variation in disease severity caused by Phytophthora cinnamomi, P. plurivora, and Pythium cryptoirregulare on two rhododendron cultivars

USDA-ARS?s Scientific Manuscript database

Rhododendrons are an important component of the ornamental nursery industry, but are prone to Phytophthora root rot. Phytophthora root rot is a continuing issue on rhododendrons despite decades of research. Several Phytophthora species are known to cause root rot, but most research has focused on P....

Chitosan and oligochitosan enhance ginger (Zingiber officinale Roscoe) resistance to rhizome rot caused by Fusarium oxysporum in storage

USDA-ARS?s Scientific Manuscript database

The ability of chitosan and oligochitosan to enhance the resistance of ginger (Zingiber officinale) to rhizome rot, caused by Fusarium oxysporum, in storage was investigated. Both chitosan and oligochitosan at 1 and 5 g/L significantly inhibited rhizome rot, relative to the untreated control, with...

Pruning of Manchurian crabapple for management of speck rot and Sphaeropsis rot in apple

USDA-ARS?s Scientific Manuscript database

Phacidiopycnis washingtonensis and Sphaeropsis pyriputrescens are two important quarantined fungal pathogens that cause post-harvest speck rot and Sphaeropsis rot, respectively, in apple. Due to detection of these pathogens in fruit shipments and quarantine regulation, export of apple from Washingto...

Evaluation of soybean genotypes for resistance to charcoal rot

USDA-ARS?s Scientific Manuscript database

Charcoal rot caused by Macrophomina phaseolina causes more yield loss in soybean than most other diseases in the southern U.S.A. There are no commercial genotypes marketed as resistant to charcoal rot of soybean. Reactions of 27 maturity group (MG) III, 29 Early MG IV, 34 Late MG IV, and 59 MG V gen...

Mucor rot - An emerging postharvest disease of mandarin fruit caused by Mucor piriformis and other Mucor spp. in California

USDA-ARS?s Scientific Manuscript database

In recent years, an emerging, undescribed postharvest fruit rot disease was observed on mandarin fruit after extended storage in California. We collected decayed mandarin fruit from three citrus packinghouses in the Central Valley of California in 2015 and identified this disease as Mucor rot caused...

Expression levels of antimicrobial peptide tachyplesin I in transgenic Ornithogalum lines affect the resistance to Pectobacterium infection.

PubMed

Lipsky, Alexander; Joshi, Janak Raj; Carmi, Nir; Yedidia, Iris

2016-11-20

The genus Ornithogalum includes several ornamental species that suffer substantial losses from bacterial soft rot caused by Pectobacteria. The absence of effective control measures for use against soft rot bacteria led to the initiation of a project in which a small antimicrobial peptide from an Asian horseshoe crab, tachyplesin (tpnI), was introduced into two commercial cultivars: O. dubium and O. thyrsoides. Disease severity and bacterial colonization were examined in transgenic lines expressing this peptide. Disease resistance was evaluated in six lines of each species by measuring bacterial proliferation in the plant tissue. Three transgenic lines of each species were subjected to further analysis in which the expression level of the transgene was evaluated using RT-PCR and qRT-PCR. The development of disease symptoms and bacterial colonization of the plant tissue were also examined using GFP-expressing strain of P. carotovorum subsp. brasiliense Pcb3. Confocal-microscopy imaging revealed significantly reduced quantities of bacterial cells in the transgenic plant lines that had been challenged with the bacterium. The results clearly demonstrate that tpnI expression reduces bacterial proliferation, colonization and disease symptom (reduced by 95-100%) in the transgenic plant tissues. The quantity of tpnI transcripts, as measured by qRT-PCR, was negatively correlated with the protection afforded to the plants, as measured by the reduced severity of disease symptoms in the tissue. Copyright © 2016 Elsevier B.V. All rights reserved.

Nitric oxide detoxification by Fusarium verticillioides flavohemoglobin and role in pathogenicity of maize

USDA-ARS?s Scientific Manuscript database

Fusarium verticillioides is a non-obligate plant pathogen of maize causing a number of specific diseases, including root rot, kernel rot, seed rot, stalk rot, and seedling blight. The saprophytic nature of this fungus, its production of the mycotoxin fumonisin, and complex relationship maize puts t...

Cultivar selection for bacterial root rot in sugar beet

USDA-ARS?s Scientific Manuscript database

Bacterial root rot of sugar beet caused by Leuconostoc mesenteroides subsp. dextranicum is a disease problem recently described in the United States, which has frequently been found in association with Rhizoctonia root rot. To reduce the impact of bacterial root rot on sucrose loss in the field, st...

Characterizing butt-rot fungi on USA-affiliated islands in the western Pacific

Treesearch

Phil Cannon; Ned B. Klopfenstein; Robert L. Schlub; Mee-Sook Kim; Yuko Ota; Norio Sahashi; Roland J. Quitugua; John W. Hanna; Amy L. Ross-Davis; J. D. Sweeney

2014-01-01

Ganoderma and Phellinus are genera that commonly cause tree butt-rot on USA-affiliated islands of the western Pacific. These fungal genera can be quite prevalent, especially in older mangrove stands. Although the majority of infections caused by these fungi lead to severe rotting of the heartwood, they typically do not directly kill the living tissues of the sapwood,...

HOW to Identify and Minimize White Trunk Rot of Aspen

Treesearch

Michael E. Ostry; James W. Walters

1983-01-01

Phellinus tremulae (=Fomes ignarius var populinus) causes a heart rot of aspen that causes more volume loss than any other disease of aspen. Severity of the disease increases with stand age. In fact, incidence of white trunk rot is a major consideration in determining aspen rotations. Although no consistent relation exists between site and decay, generally less volume...

Selection and validation of enzymatic activities as functional markers in wood biotechnology and fungal ecology.

PubMed

Mathieu, Yann; Gelhaye, Eric; Dumarçay, Stéphane; Gérardin, Philippe; Harvengt, Luc; Buée, Marc

2013-02-15

The dead wood and forest soils are sources of diversity and under-explored fungal strains with biotechnological potential, which require to be studied. Numerous enzymatic tests have been proposed to investigate the functional potential of the soil microbial communities or to test the functional abilities of fungal strains. Nevertheless, the diversity of these functional markers and their relevance in environmental studies or biotechnological screening does still have not been demonstrated. In this work, we assessed ten different extracellular enzymatic activities involved in the wood decaying process including β-etherase that specifically cleaves the β-aryl ether linkages in the lignin polymer. For this purpose, a collection of 26 fungal strains, distributed within three ecological groups (white, brown and soft rot fungi), has been used. Among the ten potential functional markers, the combinatorial use of only six of them allowed separation between the group of white and soft rot fungi from the brown rot fungi. Moreover, our results suggest that extracellular β-etherase is a rare and dispensable activity among the wood decay fungi. Finally, we propose that this set of markers could be useful for the analysis of fungal communities in functional and environmental studies, and for the selection of strains with biotechnological interests. Copyright © 2012 Elsevier B.V. All rights reserved.

Characterizing forest root‐ and butt‐rot fungi in Yap, Palau, Pohnpei, Kosrae, Guam and Saipan [Chapter III

Treesearch

Phil Cannon; Ned B. Klopfenstein; Mee-Sook Kim; Yuko Ota; Norio Sahashi; Robert L. Schlub; Roger Brown; Sara M. Ashiglar; Amy L. Ross-Davis; John W. Hanna

2014-01-01

Ganoderma and Phellinus are two common fungal genera causing butt-rot on trees growing on USA-affiliated islands of the western Pacific. Although these fungi can be quite prevalent, especially in some older mangrove stands, it appears that the majority of infections caused by these fungi leads to severe rotting of the heartwood but do not kill the living...

Occurrence of Root Rot and Vascular Wilt Diseases in Roselle (Hibiscus sabdariffa L.) in Upper Egypt.

PubMed

Hassan, Naglaa; Shimizu, Masafumi; Hyakumachi, Mitsuro

2014-03-01

Roselle (Hibiscus sabdariffa L.) family Malvaceae is an important crop used in food, cosmetics and pharmaceutics industries. Roselle is cultivated mainly in Upper Egypt (Qena and Aswan governorates) producing 94% of total production. Root rot disease of roselle is one of the most important diseases that attack both seedlings and adult plants causing serious losses in crop productivity and quality. The main objective of the present study is to identify and characterize pathogens associated with root rot and wilt symptoms of roselle in Qena, Upper Egypt and evaluate their pathogenicity under greenhouse and field condition. Fusarium oxysporum, Macrophomina phaseolina, Fusarium solani, Fusarium equiseti and Fusarium semitectum were isolated from the natural root rot diseases in roselle. All isolated fungi were morphologically characterized and varied in their pathogenic potentialities. They could attack roselle plants causing damping-off and root rot/wilt diseases in different pathogenicity tests. The highest pathogenicity was caused by F. oxysporum and M. phaseolina followed by F. solani. The least pathogenic fungi were F. equiseti followed by F. semitectum. It obviously noted that Baladi roselle cultivar was more susceptible to infection with all tested fungi than Sobhia 17 under greenhouse and field conditions. This is the first report of fungal pathogens causing root rot and vascular wilt in roselle in Upper Egypt.

Cacao diseases: A history of old enemies and new encounters

USDA-ARS?s Scientific Manuscript database

This book reviews the current knowledge of cacao pathogens and their management methods. Topics discussed include the history, biology, and genetic diversity of Moniliophthora (causing witches’ broom and frosty pod rot) and Phytophthora species (causing black pod rot) that cause diseases resulting i...

The emerging contribution of social wasps to grape rot disease ecology

PubMed Central

Boyden, Sean D.; Soriano, Jonathan-Andrew N.; Corey, Tyler B.; Leff, Jonathan W.; Fierer, Noah; Starks, Philip T.

2017-01-01

Grape sour (bunch) rot is a polymicrobial disease of vineyards that causes millions of dollars in lost revenue per year due to decreased quality of grapes and resultant wine. The disease is associated with damaged berries infected with a community of acetic acid bacteria, yeasts, and filamentous fungi that results in rotting berries with high amounts of undesirable volatile acidity. Many insect species cause the initial grape berry damage that can lead to this disease, but most studies have focused on the role of fruit flies in facilitating symptoms and vectoring the microorganisms of this disease complex. Like fruit flies, social wasps are abundant in vineyards where they feed on ripe berries and cause significant damage, while also dispersing yeasts involved in wine fermentation. Despite this, their possible role in disease facilitation and dispersal of grape rots has not been explored. We tested the hypothesis that the paper wasp Polistes dominulus could facilitate grape sour rot in the absence of other insect vectors. Using marker gene sequencing we characterized the bacterial and fungal community of wild-caught adults. We used a sterilized foraging arena to determine if these wasps transfer viable microorganisms when foraging. We then tested if wasps harboring their native microbial community, or those inoculated with sour rot, had an effect on grape sour rot incidence and severity using a laboratory foraging arena. We found that all wasps harbor some portion of the sour rot microbial community and that they have the ability to transfer viable microorganisms when foraging. Foraging by inoculated and uninoculated wasps led to an increase in berry rot disease symptom severity and incidence. Our results indicate that paper wasps can facilitate sour rot diseases in the absence of other vectors and that the mechanism of this facilitation may include both increasing host susceptibility and transmitting these microbial communities to the grapes. Social wasps are understudied but relevant players in the sour rot ecology of vineyards. PMID:28462032

QTLs for Resistance to Major Rice Diseases Exacerbated by Global Warming: Brown Spot, Bacterial Seedling Rot, and Bacterial Grain Rot.

PubMed

Mizobuchi, Ritsuko; Fukuoka, Shuichi; Tsushima, Seiya; Yano, Masahiro; Sato, Hiroyuki

2016-12-01

In rice (Oryza sativa L.), damage from diseases such as brown spot, caused by Bipolaris oryzae, and bacterial seedling rot and bacterial grain rot, caused by Burkholderia glumae, has increased under global warming because the optimal temperature ranges for growth of these pathogens are relatively high (around 30 °C). Therefore, the need for cultivars carrying genes for resistance to these diseases is increasing to ensure sustainable rice production. In contrast to the situation for other important rice diseases such as blast and bacterial blight, no genes for complete resistance to brown spot, bacterial seedling rot or bacterial grain rot have yet been discovered. Thus, rice breeders have to use partial resistance, which is largely influenced by environmental conditions. Recent progress in molecular genetics and improvement of evaluation methods for disease resistance have facilitated detection of quantitative trait loci (QTLs) associated with resistance. In this review, we summarize the results of worldwide screening for cultivars with resistance to brown spot, bacterial seedling rot and bacterial grain rot and we discuss the identification of QTLs conferring resistance to these diseases in order to provide useful information for rice breeding programs.

Plant growth and resistance promoted by Streptomyces spp. in tomato.

PubMed

Dias, Maila P; Bastos, Matheus S; Xavier, Vanessa B; Cassel, Eduardo; Astarita, Leandro V; Santarém, Eliane R

2017-09-01

Plant Growth Promoting Rhizobacteria (PGPR) represent an alternative to improve plant growth and yield as well as to act as agents of biocontrol. This study characterized isolates of Streptomyces spp. (Stm) as PGPR, determined the antagonism of these isolates against Pectobacterium carotovorum subsp. brasiliensis (Pcb), evaluated the ability of Stm on promoting growth and modulating the defense-related metabolism of tomato plants, and the potential of Stm isolates on reducing soft rot disease in this species. The VOC profile of Stm was also verified. Promotion of plant growth was assessed indirectly through VOC emission and by direct interaction with Stm isolates in the roots. Evaluation of soft rot disease was performed in vitro on plants treated with Stm and challenged with Pcb. Enzymes related to plant defense were then analyzed in plants treated with three selected isolates of Stm, and PM1 was chosen for further Pcb-challenging experiment. Streptomyces spp. isolates displayed characteristics of PGPR. PM3 was the isolate with efficient antagonism against Pcb by dual-culture. Most of the isolates promoted growth of root and shoot of tomato plants by VOC, and PM5 was the isolate that most promoted growth by direct interaction with Stm. Soft rot disease and mortality of plants were significantly reduced when plants were treated with StmPM1. Modulation of secondary metabolism was observed with Stm treatment, and fast response of polyphenoloxidases was detected in plants pretreated with StmPM1 and challenged with Pcb. Peroxidase was significantly activated three days after infection with Pcb in plants pretreated with StmPM1. Results suggest that Streptomyces sp. PM1 and PM5 have the potential to act as PGPR. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Genetic variation in Pythium myriotylum based on SNP typing and development of a PCR-RFLP detection of isolates recovered from Pythium soft rot ginger.

PubMed

Le, D P; Smith, M K; Aitken, E A B

2017-10-01

Pythium myriotylum is responsible for severe losses in both capsicum and ginger crops in Australia under different regimes. Intraspecific genomic variation within the pathogen might explain the differences in aggressiveness and pathogenicity on diverse hosts. In this study, whole genome data of four P. myriotylum isolates recovered from three hosts and one Pythium zingiberis isolate were derived and analysed for sequence diversity based on single nucleotide polymorphisms (SNPs). A higher number of true and unique SNPs occurred in P. myriotylum isolates obtained from ginger with symptoms of Pythium soft rot (PSR) in Australia compared to other P. myriotylum isolates. Overall, SNPs were discovered more in the mitochondrial genome than those in the nuclear genome. Among the SNPs, a single substitution from the cytosine (C) to the thymine (T) in the partially sequenced CoxII gene of 14 representatives of PSR P. myriotylum isolates was within a restriction site of HinP1I enzyme which was used in the PCR-RFLP for detection and identification of the isolates without sequencing. The PCR-RFLP was also sensitive to detect PSR P. myriotylum strains from artificially infected ginger without the need for isolation for pure cultures. This is the first study of intraspecific variants of Pythium myriotylum isolates recovered from different hosts and origins based on single nucleotide polymorphism (SNP) genotyping of multiple genes. The SNPs discovered provide valuable makers for detection and identification of P. myriotylum strains initially isolated from Pythium soft rot (PSR) ginger by using PCR-RFLP of the CoxII locus. The PCR-RFLP was also sensitive to detect P. myriotylum directly from PSR ginger sampled from pot trials without the need of isolation for pure cultures. © 2017 The Society for Applied Microbiology.

Stem rots of oil palm caused by Ganoderma boninense: pathogen biology and epidemiology.

PubMed

Pilotti, C A

2005-01-01

Oil palm (Elaeis guineensis Jacq.) has been grown in Papua New Guinea since the early 1960s. The most important disease of oil palm in PNG is a stem rot of the palm base. This is the same disease that constitutes a major threat to sustainable oil palm production in SE Asia. Investigations into the causal pathogen have revealed that the stem rots in PNG are caused predominantly by the basidiomycete Ganoderma boninense, with a minor pathogen identified as G. tornatum G. tornatum was found to have a broad host range whereas G. boninense appears to be restricted to palms. The population structure of G. boninense was investigated using inter-fertility studies between isolates collected from basal stem rots on oil palm. Although the G. boninense field populations are predominantly comprised of distinct individuals, a number of isolates were found that share single mating alleles. This indicates that out-crossing had occurred over several generations in the resident or wild population of G. boninense prior to colonization of oil palm. No direct hereditary relationship between isolates on neighbouring diseased palms was found, although an indirect link between isolates causing upper stem rot and basal stem rot was detected.

Gibberella ear rot of maize (Zea mays) in Nepal: distribution of the mycotoxins nivalenol and deoxynivalenol in naturally and experimentally infected maize.

PubMed

Desjardins, Anne E; Busman, Mark; Manandhar, Gyanu; Jarosz, Andrew M; Manandhar, Hira K; Proctor, Robert H

2008-07-09

The fungus Fusarium graminearum (sexual stage Gibberella zeae) causes ear rot of maize (Zea mays) and contamination with the 8-ketotrichothecenes nivalenol (1) or 4-deoxynivalenol (2), depending on diversity of the fungal population for the 4-oxygenase gene (TRI13). To determine the importance of 1 and 2 in maize ear rot, a survey of naturally contaminated maize in Nepal was combined with experiments in the field and in a plant growth room. In the survey, 1 contamination was 4-fold more frequent than 2 contamination and 1-producers (TRI13) were isolated more than twice as frequently as 2-producers (Psi TRI13). In maize ear rot experiments, genetically diverse 1-producers and 2-producers caused ear rot and trichothecene contamination. Among strains with the same genetic background, however, 1-producers caused less ear rot and trichothecene contamination than did 2-producers. The high frequency of 1 contamination and the high virulence of many 1-producers are of concern because maize is a staple food of rural populations in Nepal and because 1 has proven to be more toxic than 2 to animals.

A Chitosan Coating Containing Essential Oil from Origanum vulgare L. to Control Postharvest Mold Infections and Keep the Quality of Cherry Tomato Fruit

PubMed Central

Barreto, Tainá A.; Andrade, Sonalle C. A.; Maciel, Janeeyre F.; Arcanjo, Narciza M. O.; Madruga, Marta S.; Meireles, Bruno; Cordeiro, Ângela M. T.; Souza, Evandro L.; Magnani, Marciane

2016-01-01

The efficacy of an edible chitosan coating (CHI; 4 mg/mL) and Origanum vulgare L. essential oil (OVEO; 1.25 μL/mL) for maintaining the quality of cherry tomato fruit during storage at room (25°C; 12 days) and cold (12°C; 24 days) temperatures was assessed. CHI and OVEO in combination showed in vitro fungicidal effects against R. stolonifer and Aspergillus niger. CHI-OVEO coating reduced the incidence of black mold and soft rot caused by these fungi in artificially contaminated cherry tomato fruit during storage at both temperatures. CHI-OVEO coating delayed the appearance of the first visible signs of black mold and soft rot in artificially contaminated cherry tomato fruit stored at room temperature by 6 days and by more than 9 days in those stored at cold temperature. At the end of storage at room and cold temperature fruit coated with CHI-OVEO showed higher firmness (>2 N/mm) and lower weight loss (>2%) compared to uncoated tomato fruit. CHI-OVEO coating delayed the decrease of lycopene, ascorbic citric acid, glucose and fructose during the storage time assessed at room or cold temperatures. The increase of catechin, myricetin, caffeic and syringic acids was higher (1–9 mg/g) in cherry tomato fruit coated with CHI-OVEO compared to uncoated fruit during the storage at both temperatures studied. CHI-OVEO coating is a feasible treatment for maintaining the storage quality of cherry tomato fruit. PMID:27877156

Paromomycin Derived from Streptomyces sp. AG-P 1441 Induces Resistance against Two Major Pathogens of Chili Pepper.

PubMed

Balaraju, Kotnala; Kim, Chang-Jin; Park, Dong-Jin; Nam, Ki-Woong; Zhang, Kecheng; Sang, Mee Kyung; Park, Kyungseok

2016-09-28

This is the first report that paromomycin, an antibiotic derived from Streptomyces sp. AG-P 1441 (AG-P 1441), controlled Phytophthora blight and soft rot diseases caused by Phytophthora capsici and Pectobacterium carotovorum, respectively, in chili pepper (Capsicum annum L.). Chili pepper plants treated with paromomycin by foliar spray or soil drenching 7 days prior to inoculation with P. capsici zoospores showed significant (p < 0.05) reduction in disease severity (%) when compared with untreated control plants. The disease severity of Phytophthora blight was recorded as 8% and 50% for foliar spray and soil drench, respectively, at 1.0 ppm of paromomycin, compared with untreated control, where disease severity was 83% and 100% by foliar spray and soil drench, respectively. A greater reduction of soft rot lesion areas per leaf disk was observed in treated plants using paromomycin (1.0 μg/ml) by infiltration or soil drench in comparison with untreated control plants. Paromomycin treatment did not negatively affect the growth of chili pepper. Furthermore, the treatment slightly promoted growth; this growth was supported by increased chlorophyll content in paromomycin-treated chili pepper plants. Additionally, paromomycin likely induced resistance as confirmed by the expression of pathogenesis-related (PR) genes: PR-1, β-1,3-glucanase, chitinase, PR-4, peroxidase, and PR-10, which enhanced plant defense against P. capsici in chili pepper. This finding indicates that AG-P 1441 plays a role in pathogen resistance upon the activation of defense genes, by secretion of the plant resistance elicitor, paromomycin.

Tolerance to Phytophthora Fruit Rot in Watermelon Plant Introductions

USDA-ARS?s Scientific Manuscript database

Phytophthora capsici is distributed worldwide, and is an aggressive pathogen with a broad host range infecting solanaceous, leguminaceous, and cucurbitaceous crops. Fruit rot, caused by P. capsici is an emerging disease in most watermelon producing regions of Southeast US. Resistance to fruit rot o...

Jasmonic acid and salicylic acid inhibit growth of three sugarbeet storage rot pathogens

USDA-ARS?s Scientific Manuscript database

Storage rots contribute to postharvest losses by consuming sucrose and increasing carbohydrate impurities that increase sugar loss to molasses during processing. They also increase root respiration rate, which causes additional sucrose loss and contributes to pile warming. Currently, storage rots ...

Sugarbeet Cultivar Evaluation for Bacterial Root Rot

USDA-ARS?s Scientific Manuscript database

Bacterial root rot of sugarbeet caused by Leuconostoc mesenteroides subsp. dextranicum is a disease problem recently described in the United States. To ameliorate the impact of bacterial root rot on sucrose loss in the field, storage piles, and factories, studies were conducted to establish an assa...

Occurrence of Root Rot and Vascular Wilt Diseases in Roselle (Hibiscus sabdariffa L.) in Upper Egypt

PubMed Central

Hassan, Naglaa; Shimizu, Masafumi

2014-01-01

Roselle (Hibiscus sabdariffa L.) family Malvaceae is an important crop used in food, cosmetics and pharmaceutics industries. Roselle is cultivated mainly in Upper Egypt (Qena and Aswan governorates) producing 94% of total production. Root rot disease of roselle is one of the most important diseases that attack both seedlings and adult plants causing serious losses in crop productivity and quality. The main objective of the present study is to identify and characterize pathogens associated with root rot and wilt symptoms of roselle in Qena, Upper Egypt and evaluate their pathogenicity under greenhouse and field condition. Fusarium oxysporum, Macrophomina phaseolina, Fusarium solani, Fusarium equiseti and Fusarium semitectum were isolated from the natural root rot diseases in roselle. All isolated fungi were morphologically characterized and varied in their pathogenic potentialities. They could attack roselle plants causing damping-off and root rot/wilt diseases in different pathogenicity tests. The highest pathogenicity was caused by F. oxysporum and M. phaseolina followed by F. solani. The least pathogenic fungi were F. equiseti followed by F. semitectum. It obviously noted that Baladi roselle cultivar was more susceptible to infection with all tested fungi than Sobhia 17 under greenhouse and field conditions. This is the first report of fungal pathogens causing root rot and vascular wilt in roselle in Upper Egypt. PMID:24808737

Nonchemical, cultural management strategies to suppress phytophthora root rot in northern highbush blueberry

USDA-ARS?s Scientific Manuscript database

Phytophthora cinnamomi causes root rot of highbush blueberry and decreases plant growth, yield, and profitability for growers. Fungicides can suppress root rot, but cannot be used in certified organic production systems and fungicide resistance may develop. Alternative, non-chemical, cultural manag...

Pythium and Fusarium species causing seed rot and damping-off of alfalfa

USDA-ARS?s Scientific Manuscript database

Seed rot and damping-off is an important disease of alfalfa, severely affecting stand establishment when conditions favor the disease. This disease may have been overlooked as a cause of poor stand establishment and reduced vigor of adult plants. Globally, 15 Pythium species have been found to cause...

Pythium species causing damping-off of alfalfa in Minnesota: Identification, pathogenicity and fungicide sensitivity

USDA-ARS?s Scientific Manuscript database

Damping-off and seed rot is an important disease of alfalfa, severely affecting stand establishment when conditions favor the disease. Globally, 15 Pythium species are reported to cause damping-off and seed rot of alfalfa, although surveys of species causing disease on alfalfa in Minnesota are lacki...

Root rot symptoms in sugar beet lines caused by Fusarium oxysporum f. sp. betae

USDA-ARS?s Scientific Manuscript database

The soil-borne fungus Fusarium oxysporum may cause both Fusarium yellows and Fusarium root rot diseases with severe yield losses in cultivated sugar beet worldwide. These two diseases cause similar foliar symptoms but different root response and have been proposed to be due to two distinct F. oxyspo...

First Report of Sclerotium Rot on Cymbidium Orchids Caused by Sclerotium rolfsii in Korea

PubMed Central

Lee, Seong-Chan; Lee, Jung-Sup; Soh, Jae-Woo; Kim, Su

2012-01-01

Sclerotium rot was found on Cymbidium orchids at Seosan-si, Chungcheongnam-do, Korea, in July, 2010. Symptoms occurred on low leaves, which turned yellowish, after which the entire plant wilted. Severely infected plants were blighted and eventually died. White mycelial mats and sclerotia appeared on pseudobulbs. Based on the mycological characteristics and pathogenicity, the causal fungus was identified as Sclerotium rolfsii. This is the first report of new Sclerotium rot on Cymbidium spp. caused by S. rolfsii in Korea. PMID:23323053

Evaluating host resistance to Macrophomina crown rot in strawberry

USDA-ARS?s Scientific Manuscript database

Macrophomina crown rot, caused by the soilborne fungus Macrophomina phaseolina, is an emerging pathogen in California strawberry production. When established, the pathogen can cause extensive plant decline and mortality. Host resistance will be a critical tool for managing this disease and guiding ...

Annosus Root Rot in Eastern Conifers

Treesearch

Kathryn Robbins

1984-01-01

The fungus Heterobasidion annosum (Fr.) Bref. (= Fomes annosus (Fr.) Karst.) causes a root and butt rot of conifers in many temperate parts of the world. The decay, called annosus root rot, often kills infected conifers; infected trees that survive grow more slowly and are susceptible to windthrow and bark beetle attack.

Pathogenicity and genetic diversity of Fusarium oxysporum causing soybean root rot in northeast China

USDA-ARS?s Scientific Manuscript database

Soybean is an important edible legume cultivated around the world. However, soybean production is seriously impacted by the widespread occurrence of root rot disease. In this study, genetic diversity and pathogenicity of Fusarium oxysporum associated with root rot of soybean in Heilongjiang province...

A diagnostic guide for Fusarium Root Rot of pea

USDA-ARS?s Scientific Manuscript database

Fusarium root rot, caused by Fusarium solani f. sp. pisi, is a major root rot pathogen in pea production areas worldwide. Here we provide a diagnostic guide that describes: the taxonomy of the pathogen, signs and symptoms of the pathogen, host range, geographic distribution, methods used to isolate ...

Interpreting diplodiosis: bioactive metabolites in Stenocarpella maydis ear rot of maize

USDA-ARS?s Scientific Manuscript database

Stenocarpella maydis is a fungal pathogen of major importance that causes a dry-rot of maize ears and is associated with a neuromycotoxicosis in cattle grazing harvested maize fields in southern Africa and Argentina. Chemical investigations of S. maydis rotted kernels at harvest in Illinois led to t...

Fungicide rotation schemes for managing Phytophthora fruit rot of watermelon across southeastern United States

USDA-ARS?s Scientific Manuscript database

Southeastern states produce about 50% of the watermelons in the United States (U.S.) where conditions are optimal for development of Phytophthora fruit rot prevail. Phytophthora fruit rot significantly limits watermelon production by causing serious yield losses to growers before and after harvest. ...

Cultivar Selection for Sugar Beet Root Rot Resistance

USDA-ARS?s Scientific Manuscript database

Fungal and bacterial root rots in sugar beet caused by Rhizoctonia solani (Rs) and Leuconostoc mesenteroides subsp. dextranicum (Lm) can lead to root yield losses greater than 50%. To reduce the impact of these root rots on sucrose loss in the field, storage, and factories, studies were conducted t...

Cultivar selection for sugarbeet root rot resistance.

USDA-ARS?s Scientific Manuscript database

Fungal and bacterial root rots in sugar beet caused by Rhizoctonia solani (Rs) and Leuconostoc mesenteroides subsp. dextranicum (Lm) can lead to root yield losses greater than 50%. To reduce the impact of these root rots on sucrose loss in the field, storage, and factories, studies were conducted t...

Spatiotemporal characterization of Sclerotinia crown rot epidemics in pyrethrum

USDA-ARS?s Scientific Manuscript database

Sclerotinia crown rot, caused by Sclerotinia minor and S. sclerotiorum is a disease of pyrethrum in Australia that may cause substantial decline in plant density. The spatiotemporal characteristics of the disease were quantified in 14 fields spread across three growing seasons. Fitting the binary ...

Seed rot and damping-off of alfalfa in Minnesota caused by Pythium and Fusarium species

USDA-ARS?s Scientific Manuscript database

Globally, 15 Pythium species have been found to cause damping-off and seed rot of alfalfa, although surveys of species causing disease on alfalfa in the Midwestern U.S. are lacking. Pathogens were isolated by a seedling baiting technique from soil of five alfalfa fields in Minnesota with high levels...

First report of Botryosphearia dothidea causing white rot on apple fruit in Maryland

USDA-ARS?s Scientific Manuscript database

Botryosphaeria dothidea [Fr. : Moug.] Ces. & De Not. infects over 80 genera of woody plants causing stem cankers on grapevine, apple, pear, and almond trees and also causes white rot on apple fruit in the field and during storage. A B. dothidea isolate was obtained from decayed ‘Fuji’ apple fruit ex...

Decay causes little loss in hickory

Treesearch

Frederick H. Berry; John A. Beaton

1972-01-01

A study of 600 hickory trees indicated that heart-rot fungi cause little economic loss in species of the genus Carya. More than half of the decay volume for which a fungus could be identified was caused by Poria spiculosa, one of seven species of heart-rot fungi associated with decay in hickory that were isolated and identified....

Expression and characterization of aiiA gene from Bacillus subtilis BS-1.

PubMed

Pan, Jieru; Huang, Tianpei; Yao, Fan; Huang, Zhipeng; Powell, Charles A; Qiu, Sixin; Guan, Xiong

2008-01-01

AHL-lactonase (AiiA), a metallo-beta-lactamase produced by Bacillus thuringiensis, Bacillus cereus and Bacillus anthracis, specifically hydrolyzes N-acyl-homoserine lactones (AHLs) secreted by Gram-negative bacteria and thereby attenuates the symptoms caused by plant pathogens. In this study, an aiiA gene was cloned from Bacillus subtilis BS-1 by PCR with a pair of degenerate primers. The deduced 250 amino acid sequence contained two small conserved regions, 103SHLHFDH109 and 166TPGHTPGH173, which are characteristic of the metallo-beta-lactamase family. Homology comparison revealed that the deduced amino acid sequence had a high degree of similarity with those of the known AiiA proteins in the B. cereus group. Additionally, the aiiA gene was expressed in Escherichia coli BL21 (DE3) pLysS and the expressed AiiA protein could attenuate the soft rot symptoms caused by Erwinia carotovora var. carotovora.

The persistence of Gliocephalotrichum bulbilium and G. simplex causing fruit rot of rambutan in Puerto Rico

USDA-ARS?s Scientific Manuscript database

Fruit rot of rambutan (Nephelium lappaceum L.) is a pre and post-harvest disease problem that affects fruit quality. Significant post-harvest losses have occurred worldwide and several pathogens have been identified in Malaysia, Costa Rica, Hawaii, Thailand, and Puerto Rico. In 2011, fruit rot was o...

First report of Calonectria hongkongensis causing fruit rot of rambutan (Nephelium lappaceum L.)

USDA-ARS?s Scientific Manuscript database

Fruit rot is a major pre- and post-harvest disease problem in rambutan orchards. In 2011, fruit rot was observed at the USDA-TARS orchards in Mayaguez, Puerto Rico. Infected fruit were collected and tissue sections (1 mm2) were superficially sterilized with 70% ethanol and 0.5% sodium hypochlorite. ...

Influence of Rhizoctonia-Bacterial root rot complex on storability of sugar beet

USDA-ARS?s Scientific Manuscript database

The root rot complex, caused by Rhizoctonia solani and Leuconostoc mesenteroides, can lead to yield loss in the field but may also lead to problems with sucrose loss in storage. Thus, studies were conducted to investigate if placing sugar beet roots suffering from root rot together with healthy roo...

Sorghum pathology and biotechnology - A fungal disease perspective: Part II. Anthracnose, stalk rot, and downy mildew

USDA-ARS?s Scientific Manuscript database

Foliar diseases and stalk rots are among the most damaging diseases of sorghum in terms of lost production potential, thus commanding considerable research time and expenditure. This review will focus on anthracnose, a fungal disease that causes both foliar symptoms and stalk rots along with the st...

Postharvest salicylic acid treatment reduces storage rots in water-stressed but no unstressed sugarbeet roots

USDA-ARS?s Scientific Manuscript database

Exogenous application of salicylic acid (SA) reduces storage rots in a number of postharvest crops. SA’s ability to protect sugarbeet (Beta vulgaris L.) taproots from common storage rot pathogens, however, is unknown. To determine the potential of SA to reduce storage losses caused by three common...

Commercial Sugar Beet Cultivars Evaluated for Resistance to Bacterial Root Rot in Idaho, 2008

USDA-ARS?s Scientific Manuscript database

Bacterial root rot of sugar beet caused by Leuconostoc mesenteroides subsp. dextranicum is a disease problem recently described in the United States. To ameliorate the impact of bacterial root rot on sucrose loss in the field, storage piles, and factories, a study was conducted to identify resistan...

Experimental Sugar Beet Cultivars Evaluated for Resistance Bacterial Root Rot in Idaho, 2008

USDA-ARS?s Scientific Manuscript database

Bacterial root rot of sugar beet caused by Leuconostoc mesenteroides subsp. dextranicum is a disease problem recently described in the United States. To ameliorate the impact of bacterial root rot on sucrose loss in the field, storage piles, and factories, a study was conducted to identify resistan...

Influence of sugarbeet tillage Systems on the rhizoctonia-bacterial root rot complex

USDA-ARS?s Scientific Manuscript database

The Rhizoctonia-bacterial root rot complex in sugarbeet caused by Rhizoctonia solani and Leuconostoc mesenteroides can cause significant yield losses. To investigate the impact of different tillage systems on this complex, field studies were conducted from 2009 to 2011. Split blocks with conventio...

Influence of sugarbeet tillage systems on rhizoctonia-bacterial root rot complex

USDA-ARS?s Scientific Manuscript database

The Rhizoctonia-bacterial root rot complex on sugarbeet caused by Rhizoctonia solani and Leuconostoc mesenteroides can cause significant yield losses. To investigate the impact of different tillage systems on this complex, field studies were conducted from 2009 to 2011. Split blocks with conventio...

78 FR 25939 - Submission for OMB Review; Comment Request

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-03

... Inspection Service Title: Certification Program for Imported Articles to Prevent Introduction of Potato Brown... to occur. This bacterial strain causes potato brown rot, which causes potatoes to rot through, making them inedible and seriously affecting potato yields. Need and Use of the Information: The Animal Plant...

Bull’s-eye rot management: understanding the disease cycle of Neofabraea spp. occurring on apples grown in the Pacific Northwest

USDA-ARS?s Scientific Manuscript database

In the US Pacific Northwest, bull’s-eye rot of pome fruit, caused by Neofabraea spp., is a major quarantine concern. Of the four fungi causing this disease, Neofabraea perennans and N. kienholzii are common in north central Washington. In addition to fruit decay, N. perennans causes perennial cank...

Development and application of qPCR and RPA genus and species-specific detection of Phytophthora sojae and Phytophthora sansomeana root rot pathogens of soybean

USDA-ARS?s Scientific Manuscript database

Phytophthora root rot of soybean, caused by Phytophthora sojae is one of the most important diseases in the Midwest US, causing losses of up to 44 million bushels per year. Disease may also be caused by P. sansomeana, however the prevalence and damage caused by this species is not well known, partl...

Influence of tillage systems on Rhizoctonia-bacterial root rot complex in sugar beet

USDA-ARS?s Scientific Manuscript database

The Rhizoctonia-bacterial root rot complex on sugarbeet caused by Rhizoctonia solani and Leuconostoc mesenteroides can cause significant yield losses. To investigate the impact of different tillage systems on this complex, field studies were conducted from 2009 to 2011. Split blocks with conventio...

Meiotic drive-based strategy to minimize mycotoxins in corn

USDA-ARS?s Scientific Manuscript database

Some fungi pose a dual threat to corn production by causing disease (seedling, root, stalk or ear rots) and by producing mycotoxins that pose health risks to humans and domestic animals. For example, the fungus Fusarium verticillioides can cause stalk and ear rot of corn and produce fumonisins, a fa...

Loop-mediated isothermal amplification (LAMP) based detection of Colletotrichum falcatum causing red rot in sugarcane

USDA-ARS?s Scientific Manuscript database

Red rot, caused by Colletotrichum falcatum, is a destructive disease prevalent in most sugarcane-producing countries. Disease-free sugarcane planting materials are essential as the pathogen spreads primarily through infected setts. The present study was undertaken to develop loop-mediated isothermal...

Huanglongbing increases Diplodia Stem End Rot in Citrus sinensis

USDA-ARS?s Scientific Manuscript database

Huanglongbing (HLB), one of the most devastating diseases of citrus is caused by the a-Proteobacteria Candidatus Liberibacter. Diplodia natalensis Pole-Evans is a fungal pathogen which has been known to cause a postharvest stem-end rot of citrus, the pathogen infects citrus fruit under the calyx, an...

[Toxicity of Pythium oligandrum broth to animal and its control effect on rot diseases caused by Penicillium italicum and Penicillium digitatum in orange fruit storage].

PubMed

Tan, Yan; Peng, Liangzhi; Yuan, Ling; Wang, Shaobo

2015-11-04

In order to develop a safe, nontoxic and efficient biological antistaling agent and to decrease the incidence of rot diseases caused by the Penicillium italicum and Penicillium digitatum in orange fruit storage. the present experiment was carried out with Pythium oligandrum broth (POB) produced by our self-isolated strain (P. oligandrum CQ2010) to study the toxicity to animal. Thereafter, mycelium growth and spore germination of both P. digitatum and P. italicum and control effect of rot disease in orange storage were compared after treated by liquid culture medium (control), POB, prochloraz (PC) , and PC + POB. Gastric lavage with large amount POB did not influence mouse weight. The animals also showed no abnormality in appearance, behaviors and pathology changes in heart, liver, kidney, lung and intestine. POB decreased the hyphal growth by 70.24% - 93.74% and spore germination by 44.91% - 87.82% (24 h after POB addition) of these two pathogenic fungi. Disease incidence of orange fruit following P. italicum inoculation changed in the sequence: CK > POB > PC > PC + POB and the control efficacy behaved otherwise. In commercial simulation storage, the disease incidence of orange fruit caused by P. digitatum and P. italicum was above 50% of the total. The fruit rot rate was 26.40% (CK), 15.03% (POB), 16.61% (PC) and 4.21% (PC + POB). There were no significant differences in fruit quality under different treatments. POB was safe to animal and could decrease rot disease incidence caused by P. italicum and P. digitatum in orange storage whereby producing a positive interaction with prochloraz and controlling rot diseases caused by these two fungi.

Highly uniform residual layers for arrays of 3D nanoimprinted cavities in Fabry-Pérot-filter-array-based nanospectrometers

NASA Astrophysics Data System (ADS)

Memon, Imran; Shen, Yannan; Khan, Abdullah; Woidt, Carsten; Hillmer, Hartmut

2016-04-01

Miniaturized optical spectrometers can be implemented by an array of Fabry-Pérot (FP) filters. FP filters are composed of two highly reflecting parallel mirrors and a resonance cavity. Each filter transmits a small spectral band (filter line) depending on its individual cavity height. The optical nanospectrometer, a miniaturized FP-based spectrometer, implements 3D NanoImprint technology for the fabrication of multiple FP filter cavities in a single process step. However, it is challenging to avoid the dependency of residual layer (RL) thickness on the shape of the printed patterns in NanoImprint. Since in a nanospectrometer the filter cavities vary in height between neighboring FP filters and, thus, the volume of each cavity varies causing that the RL varies slightly or noticeably between different filters. This is one of the few disadvantages of NanoImprint using soft templates such as substrate conformal imprint lithography which is used in this paper. The advantages of large area soft templates can be revealed substantially if the problem of laterally inhomogeneous RLs can be avoided or reduced considerably. In the case of the nanospectrometer, non-uniform RLs lead to random variations in the designed cavity heights resulting in the shift of desired filter lines. To achieve highly uniform RLs, we report a volume-equalized template design with the lateral distribution of 64 different cavity heights into several units with each unit comprising four cavity heights. The average volume of each unit is kept constant to obtain uniform filling of imprint material per unit area. The imprint results, based on the volume-equalized template, demonstrate highly uniform RLs of 110 nm thickness.

pH-Dependent DNA Distortion and Repression of Gene Expression by Pectobacterium atrosepticum PecS.

PubMed

Deochand, Dinesh K; Meariman, Jacob K; Grove, Anne

2016-07-15

Transcriptional activity is exquisitely sensitive to changes in promoter DNA topology. Transcription factors may therefore control gene activity by modulating the relative positioning of -10 and -35 promoter elements. The plant pathogen Pectobacterium atrosepticum, which causes soft rot in potatoes, must alter gene expression patterns to ensure growth in planta. In the related soft-rot enterobacterium Dickeya dadantii, PecS functions as a master regulator of virulence gene expression. Here, we report that P. atrosepticum PecS controls gene activity by altering promoter DNA topology in response to pH. While PecS binds the pecS promoter with high affinity regardless of pH, it induces significant DNA distortion only at neutral pH, the pH at which the pecS promoter is repressed in vivo. At pH ∼8, DNA distortions are attenuated, and PecS no longer represses the pecS promoter. A specific histidine (H142) located in a crevice between the dimerization- and DNA-binding regions is required for pH-dependent changes in DNA distortion and repression of gene activity, and mutation of this histidine renders the mutant protein incapable of repressing the pecS promoter. We propose that protonated PecS induces a DNA conformation at neutral pH in which -10 and -35 promoter elements are suboptimally positioned for RNA polymerase binding; on deprotonation of PecS, binding is no longer associated with significant changes in DNA conformation, allowing gene expression. We suggest that this mode of gene regulation leads to differential expression of the PecS regulon in response to alkalinization of the plant apoplast.

Progress of Heart Rot Following Fire in Bottomland Red Oaks

Treesearch

E. Richard Toole; George M. Furnival

1957-01-01

The most important cause of cull in southern hardwood forests is heart rot that develops from wounds made by fire. This study derived means by which the forester working with bottomland red oaks can determine the amount of decay behind old fire scars and estimate the rot that can be expected from new wounds.

Interactions of Salmonella enterica Serovar Typhimurium and Pectobacterium carotovorum within a tomato soft rot

USDA-ARS?s Scientific Manuscript database

The human pathogen Salmonella has shown a remarkable adaptability which allows these bacteria to thrive in a variety of environments and hosts. The manner in which these pathogens establish within a niche amidst the native microbiota remains poorly understood. Here, we aimed to uncover the mechanism...

Incidence of bacterial diseases associated with irrigation methods on onions (Allium cepa).

PubMed

Chorolque, A; Pozzo Ardizzi, C; Pellejero, G; Aschkar, G; García Navarro, F J; Jiménez Ballesta, R

2018-04-24

In the last decade, diseases of bacterial origin in onions have increased and this has led to significant losses in production. These diseases are currently observed in both the Old and New Worlds. The aim of the experimental work reported here was to evaluate whether the irrigation method influences the incidence of diseases of bacterial origin. In cases where the inoculum was natural, the initial incidence of Soft Bacterial Rot was not manifested in any treatment in the first year, whereas at the end of the conservation period all treatments had increased incidences of infection. Sprinkler irrigation (8%) was statistically differentiated from the other treatments, for which the final incidence was similar (4.5%). For all irrigation treatments, the final incidence of Bacterial Soft Rot decreased or remained stable towards the end of the cycle, with the exception of sprinkler irrigation in 2015, which increased. It can be inferred from the results that the irrigation method does have an influence on the incidence of diseases of bacterial origin in the post-harvest stage for onions. This article is protected by copyright. All rights reserved.

Comparing methods for inducing root rot of Rhododendron with Phytophthora cinnamomi and P. plurivora

USDA-ARS?s Scientific Manuscript database

Root rot, caused by Phytophthora cinnamomi and P. plurivora in containerized Rhododendron, can cause significant losses in the nursery industry. Studies commonly use a 48 h flooding event to stimulate root infection. While flooding rarely occurs in container nurseries, plants may sit in a shallow pu...

Sources of resistance to sunflower diseases in a global collection of domesticated USDA plant introductions

USDA-ARS?s Scientific Manuscript database

Basal stalk rot (BSR) and head rot (HR) caused by Sclerotinia sclerotiorum (Lib.) de Bary are traditionally major diseases of sunflower (Helianthus annuus L.) in the United States, while Phomopsis stem canker (PSC) caused by Phomopsis helianthi Munt.-Cvet. et. al. has increasingly become damaging in...

Registration of an oilseed sunflower germplasm line HA-BSR1 highly tolerant to Sclerotinia basal stalk rot

USDA-ARS?s Scientific Manuscript database

Basal stalk rot (BSR) caused by Sclerotinia sclerotiorum (Lib.) de Bary is a devastating disease that causes a significant damage to worldwide sunflower (Helianthus annuus L.) production by reducing seed yield and quality. The objective of this research was to develop highly BSR tolerant sunflower g...

First report of frosty pod rot caused by Moniliophthora roreri on cacao in Bolivia

USDA-ARS?s Scientific Manuscript database

Frosty pod rot (FPR) is a devastating cacao disease caused by the basidiomycete Moniliophthora roreri (Aime and Phillips-Mora, 2005). The disease is confined to 13 countries in Central and South America and constitutes a permanent threat for cacao cultivation worldwide. In July 2012, FPR was detect...

Irrigation affects severity of root rot caused by Phythophthora plurivora and P. cinnamomi on rhododendron

USDA-ARS?s Scientific Manuscript database

Plant pathogens in the genus Phytophthora cause root rot that decrease product quality and result in plant death and economic losses to the nursery industry. Recently, we found Phytophthora plurivora prevalent on rhododendron in nurseries in the Pacific Northwest, USA, but there is little informatio...

Evaluation of Blackberry Cultivars Adapted to the Southeastern United States for Rosette and Post-Harvest Fruit Diseases

USDA-ARS?s Scientific Manuscript database

Rosette (caused by the fungus Cercosporella rubi) is considered a limiting factor of blackberry production in the southern U. S. Fruit rots annually cause extensive losses to blackberry farmers. The development of cultivars with increased resistance to rosette, fruit rot and other diseases should r...

Pre- and post-harvest development of Phytophthora fruit rot on watermelons treated with fungicides in the field

USDA-ARS?s Scientific Manuscript database

Fruit rot, caused by Phytophthora capsici, is a serious disease in most watermelon producing regions in southeastern U.S., and has caused devastating loss over the past few years. In many instances, severe losses occurred after harvest during transportation. Experiments were conducted in 2010, 201...

Inhibitory effect of selenium against Penicillium expansum and its possible mechanisms of action

USDA-ARS?s Scientific Manuscript database

Penicillium expansum is a widely spread fungal pathogen that causes blue mold rot in a variety of fruits. This pathogen not only induces blue mold rot but also produces patulin in affected apple fruit, a secondary metabolite that is toxic to humans and animals. Currently, diseases caused by P. expan...

Genome-wide association study of resistance to ear rot by Fusarium verticillioides in a tropical field maize and popcorn core collection

USDA-ARS?s Scientific Manuscript database

Fusarium ear rot (caused by Fusarium verticillioides) is one of the most prevalent diseases of maize worldwide, and has one of the greatest negative economic impacts on this cereal crop globally. Fusarium ear rot is a highly complex trait, under polygenic control with minor effects per gene and low ...

First report of Colletotrichum fructicola and C. queenslandicum causing fruit rot of rambutan (Nephelium lappaceum L.)

USDA-ARS?s Scientific Manuscript database

In rambutan production, fruit rot is the main pre- and post-harvest disease of concern. In a 2008-2013 fruit disease survey, fruit rot was observed in eight orchards in Puerto Rico. Infected fruit were collected and 1 mm2 tissue sections were surface disinfested with 70% ethanol followed by 0.5% sod...

First report of root rot of cowpea caused by Fusarium equiseti in Georgia in the United States

USDA-ARS?s Scientific Manuscript database

Root rot was observed on cowpea in Tift County, Georgia, in May of 2015. The disease occurred on approximately 10% of cowpea plants in 2 fields (2 ha). Symptoms appeared as sunken reddish brown lesions on roots and stems under the soil line, secondary roots became dark brown and rotted, and infected...

Strength reduction in slash pine (Pinus elliotii) wood caused by decay fungi

Treesearch

Zhong Yang; Zhehui Jiang; Chung Y. Hse; Todd F. Shupe

2009-01-01

Small wood specimens selected from slash pine (Pinus elliotii )trees at three growth rates (fast, medium, and slow) were inoculated with brown-rot and white-rot fungi and then evaluated for work to maximum load (WML), modulus of rupture (MOR), and modulus of elasticity (MOE). The experimental variables studied included a brown-rot fungus (Gloeophyllum trabeum...

Allozyme-Specific Modification of a Maize Seed Chitinase by a Protein Secreted by the Fungal Pathogen Stenocarpella maydis

USDA-ARS?s Scientific Manuscript database

Stenocarpella maydis causes both dry-ear rot and stalk rot of maize. Maize inbreds have varying levels of resistance to S. maydis ear rot. The genetic basis of resistance appears to rely on multiple genetic factors, none of which are known. The commonly used stiff stalk inbred B73 has been shown ...

Quantitative relationships between different injury factors and development of brown rot caused by Monilinia fructigena in integrated and organic apple orchards.

PubMed

Holb, I J; Scherm, H

2008-01-01

In a 4-year study, the incidence of various types of injuries (caused by insects, birds, growth cracks, mechanical wounding, and other, unidentified factors) was assessed in relation to brown rot development (caused by Monilinia fructigena) on fruit of three apple cultivars (Prima, Jonathan, and Mutsu) in integrated and organic blocks of two apple orchards in Hungary. In addition, populations of male codling moths (Cydia pomonella) were monitored with pheromone traps season-long in both management systems. On average, injury incidence on fruit at harvest was 6.1 and 19.2% in the integrated and organic treatments, respectively. Insect injury, which was caused primarily by C. pomonella, had the highest incidence among the five injury types, accounting for 79.4% of the total injury by harvest in the organic blocks and 36.6% in the integrated blocks. Levels of all other injury types remained close to zero during most of the season, but the incidence of bird injury and growth cracks increased markedly in the final 3 to 5 weeks before harvest in both production systems. Brown rot developed more slowly and reached a lower incidence in the integrated (6.4% final incidence on average) compared with the organic blocks (20.1% average incidence). In addition, the disease developed later but attained higher levels as the cultivar ripening season increased from early-maturing Prima to late-maturing Mutsu. Overall, 94.3 to 98.7% of all injured fruit were also infected by M. fructigena, whereas the incidence of brown-rotted fruit without visible injury was very low (0.8 to 1.6%). Correlation coefficients (on a per plot basis) and association indices (on a per-fruit basis) were calculated between brown rot and the various injury types for two selected assessment dates 4 weeks preharvest and at harvest. At both dates, the strongest significant (P < 0.05) relationships were observed between brown rot and insect injury and between brown rot and the cumulative number of trapped C. pomonella. At the harvest assessment, two additional significant correlations were between brown rot and bird injury and between brown rot and growth cracks. In every case, correlation coefficients were larger in organic than in integrated blocks. Although it is well established that brown rot in pome fruits is closely associated with fruit injuries, this is the first study to provide season-long progress data on different injury types and quantitative analyses of their relative importance at different times in the growing season and across two distinct management systems.

An insight into spore dispersal of Ganoderma boninense on oil palm.

PubMed

Sanderson, F R

2005-01-01

The disease of oil palm caused by Ganoderma boninense, although universally referred to as Ganoderma basal stem rot, occurs in three very distinct phases, with basal stem rot only part of the disease cycle. G. boninense also causes a seedling disease and an upper stem rot. An understanding of spore dispersal provides an insight into where spores of G. boninense have a role in the infection process. This role will be discussed in relation to each of these three infection phases. This understanding is a critical component of developing a successful disease control strategy.

Analyses between Reproductive Behavior, Genetic Diversity and Pythium Responsiveness in Zingiber spp. Reveal an Adaptive Significance for Hemiclonality

PubMed Central

Thomas, Geethu E.; Geetha, Kiran A.; Augustine, Lesly; Mamiyil, Sabu; Thomas, George

2016-01-01

Mode of reproduction is generally considered to have long-range evolutionary implications on population survival. Because sexual reproduction produces genetically diverse genotypes, this mode of reproduction is predicted to positively influence the success potential of offspring in evolutionary arms race with parasites (Red queen) whereas, without segregation and recombination, the obligate asexual multiplication may push a species into extinction due to the steady accumulation of deleterious mutations (Muller’s ratchet). However, the extent of linearity between reproductive strategies, genetic diversity and population fitness, and the contributions of different breeding strategies to population fitness are yet to be understood clearly. Genus Zingiber belonging to the pan-tropic family Zingiberaceae represents a good system to study contributions of different breeding behavior on genetic diversity and population fitness, as this genus comprises species with contrasting breeding systems. In this study, we analyzed breeding behavior, amplified fragment length polymorphism diversity and response to the soft-rot pathogen Pythium aphanidermatum in 18 natural populations of three wild Zingiber spp.: Z. neesanum, Z. nimmonii, and Z. zerumbet, together with the obligately asexual cultivated congener, ginger (Z. officinale). Ginger showed an exceptionally narrow genetic base, and adding to this, all the tested cultivars were uniformly susceptible to soft-rot. Concordant with the postulates of Muller’s ratchet, the background selection may be continuously pushing ginger into the ancestral state, rendering it inefficient in host-pathogen coevolution. Z. neesanum and Z. nimmonii populations were sexual and genetically diverse; however, contrary to Red Queen expectations, the populations were highly susceptible to soft-rot. Z. zerumbet showed a hemiclonal breeding behavior. The populations inhabiting forest understory were large and continuous, sexual and genetically diverse, but were susceptible, whereas populations inhabiting the revenue land were fragmented and monoclonal, but were resistant. It may be possible that, when genetic recombination becomes at a premium due to the genetic constraints imparted by habitat fragmentation or pathogen pressure, Z. zerumbet PMID:28066470

Associations of planting date, drought stress, and insects with Fusarium ear rot and fumonisin B1 contamination in California maize.

PubMed

Parsons, M W; Munkvold, G P

2010-05-01

Fusarium ear rot, caused by Fusarium verticillioides, is one of the most common diseases of maize, causing yield and quality reductions and contamination of grain by fumonisins and other mycotoxins. Drought stress and various insects have been implicated as factors affecting disease severity. Field studies were conducted to evaluate the interactions and relative influences of drought stress, insect infestation, and planting date upon Fusarium ear rot severity and fumonisin B1 contamination. Three hybrids varying in partial resistance to Fusarium ear rot were sown on three planting dates and subjected to four irrigation regimes to induce differing levels of drought stress. A foliar-spray insecticide treatment was imposed to induce differing levels of insect injury. Populations of thrips (Frankliniella spp.), damage by corn earworm (Helicoverpa zeae), Fusarium ear rot symptoms, and fumonisin B1 levels were assessed. There were significant effects of hybrid, planting date, insecticide treatment, and drought stress on Fusarium ear rot symptoms and fumonisin B1 contamination, and these factors also had significant interacting effects. The most influential factors were hybrid and insecticide treatment, but their effects were influenced by planting date and drought stress. The more resistant hybrids and the insecticide-treated plots consistently had lower Fusarium ear rot severity and fumonisin B1 contamination. Later planting dates typically had higher thrips populations, more Fusarium ear rot, and higher levels of fumonisin B1. Insect activity was significantly correlated with disease severity and fumonisin contamination, and the correlations were strongest for thrips. The results of this study confirm the influence of thrips on Fusarium ear rot severity in California, USA, and also establish a strong association between thrips and fumonisin B1 levels.

Detection and identification of six Monilinia spp. causing brown rot using TaqMan real-time PCR from pure cultures and infected apple fruit

USDA-ARS?s Scientific Manuscript database

Brown rot is a severe disease affecting stone and pome fruits. This disease was recently confirmed to be caused by the following six closely related species: Monilinia fructicola, Monilinia laxa, Monilinia fructigena, Monilia polystroma, Monilia mumecola and Monilia yunnanensis. Because of differenc...

Genetic architecture and evolution of the mating type locus in fusaria that cause soybean sudden death syndrome and bean root rot

USDA-ARS?s Scientific Manuscript database

Fusarium tucumaniae is the only known sexually reproducing species among the seven closely related fusaria that cause soybean sudden death syndrome (SDS) or bean root rot (BRR). Laboratory mating of F. tucumaniae required two mating-compatible strains, indicating that it is heterothallic. To assess ...

Development of Phytophthora fruit rot caused by Phytophthora capsici on resistant and susceptible watermelon fruit of different ages

USDA-ARS?s Scientific Manuscript database

Watermelon is an important crop grown in 44 states in the United States. Phytophthora fruit rot caused by Phytophthora capsici is a serious disease in the southeastern U.S., where over 50% of the watermelons are produced. The disease has resulted in severe losses to watermelon growers, especially in...

Temporal occurrence and niche preferences of Phytophthora species causing brown rot of citrus in the Central Valley of California

USDA-ARS?s Scientific Manuscript database

Brown rot of citrus fruits is caused by several species of Phytophthora and is currently of serious concern for the California citrus industry. Two species, P. syringae and P. hibernalis, are quarantine pathogens in China, a major export market for California citrus. To maintain trade and estimate t...

Resistance mechanisms to toxin-mediated charcoal rot infection in maturity group III soybean: role of seed phenol lignin soflavones sugars and seed minerals in charcoal rot resistance

USDA-ARS?s Scientific Manuscript database

Charcoal rot is a disease caused by the fungus Macrophomina phaseolina (Tassi) Goid, and thought to infect the plants through roots by a toxin-mediated mechanism, resulting in yield loss and poor seed quality, especially under drought conditions. The mechanism by which this infection occurs is not y...

Isolation screening and characterisation of local beneficial rhizobacteria based upon their ability to suppress the growth of Fusarium oxysporum f. sp. radicis-lycopersici and tomato foot and root rot

USDA-ARS?s Scientific Manuscript database

Tomato crown and root rot or tomato foot and root rot (TFRR) is caused by the phytopathogenic fungus Fusarium oxysporum f. sp. radicis-lycopersici (Forl). The disease occurs in both greenhouse and outdoor tomato cultivations and cannot be treated efficiently with the existing fungicides. We conducte...

Mechanisms of protection by NHA against fungal decay

Treesearch

Frederick Green; William Henry; Tor Schultz

2002-01-01

Treating wood with the water-borne sodium salt of N'-N-naphthaloylhydroxylamine (Na-NHA) protects wood against decay and termite damage. Initial testing indicated little or no inhibition of sapstain fungi, molds, or soft-rot fungi by Na-NHA, suggesting that the mechanism by which this compound protected wood was complex and not that of a broad-spectrum biocide....

Bacterial associations with decaying wood : a review

Treesearch

C. A. Clausen

1996-01-01

Wood-inhabiting bacteria are associated with wood decay and may have an indirect influence on the decay process. Bacteria are able to affect wood permeability, attack wood structure, or work synergistically with other bacteria and soft-rot fungi to predispose wood to fungal attack. Bacteria that can inhabit chemically treated wood are recognized. The natural ability of...

Inhibition of decay fungi using cotton cellulose hydrolysis as a model for wood decay

Treesearch

Frederick Green

2000-01-01

Environmental pressures to replace chromium and arsenic in fixed waterborne preservatives have been increasing. Potential inhibitors of brown-, white- and soft-rot fungi need to be evaluated as alternative preservatives by screening and testing in, in vitro model systems. This paper reports the inhibition of cellulose depolymerization and weight loss of selected decay...

Systematics of Plant-Pathogenic and Related Streptomyces Species Based on Phylogenetic Analyses of Multiple Gene Loci

USDA-ARS?s Scientific Manuscript database

The 10 species of Streptomyces implicated as the etiological agents in scab disease of potatoes or soft rot disease of sweet potatoes are distributed among 7 different phylogenetic clades in analyses based on 16S rRNA gene sequences, but high sequence similarity of this gene among Streptomyces speci...

Indirect selection for resistance to ear rot and leaf diseases in maize lines using biplots.

PubMed

Pereira, G S; Camargos, R B; Balestre, M; Von Pinho, R G; C Melo, W M

2015-09-21

Leaf disease and ear rot have caused reductions in maize yield in Brazil and other producer countries. Therefore, the aims of this study were to analyze the association between husked ear yield and the severity of maize white spot, gray leaf spot, helminthosporium, and ear rot caused by Fusarium verticillioides and Diplodia maydis using biplots in a mixed-model approach. The responses of 238 lines introduced to Brazil and four controls were evaluated using an incomplete block design with three replicates in two locations: Lavras and Uberlândia, Minas Gerais, Brazil. Two experiments were conducted in each location, one with F. verticillioides and the other with D. maydis. The mixed models elucidated the relationship between yield, leaf disease, and ear disease. Significant genotype x environment and genotype x pathogen interactions were observed. In conclusion, husked ear yield is more associated with ear rot than with the leaf diseases evaluated, justifying the indirect selection for resistance to kernel rot in maize-F. verticillioides and maize-D. maydis pathosystems by yield evaluation.

Rice Sheath Rot: An Emerging Ubiquitous Destructive Disease Complex

PubMed Central

Bigirimana, Vincent de P.; Hua, Gia K. H.; Nyamangyoku, Obedi I.; Höfte, Monica

2015-01-01

Around one century ago, a rice disease characterized mainly by rotting of sheaths was reported in Taiwan. The causal agent was identified as Acrocylindrium oryzae, later known as Sarocladium oryzae. Since then it has become clear that various other organisms can cause similar disease symptoms, including Fusarium sp. and fluorescent pseudomonads. These organisms have in common that they produce a range of phytotoxins that induce necrosis in plants. The same agents also cause grain discoloration, chaffiness, and sterility and are all seed-transmitted. Rice sheath rot disease symptoms are found in all rice-growing areas of the world. The disease is now getting momentum and is considered as an important emerging rice production threat. The disease can lead to variable yield losses, which can be as high as 85%. This review aims at improving our understanding of the disease etiology of rice sheath rot and mainly deals with the three most reported rice sheath rot pathogens: S. oryzae, the Fusarium fujikuroi complex, and Pseudomonas fuscovaginae. Causal agents, pathogenicity determinants, interactions among the various pathogens, epidemiology, geographical distribution, and control options will be discussed. PMID:26697031

Canker Rots in Southern Hardwoods

Treesearch

F.I. McCracken

1978-01-01

Canker-rot fungi cause serious degrade and cull in southern hardwoods, especially the red oaks. Heartwood decay is the most serious form of damage, but the fungi also kill the cambium and decay the sapwood for as much as 3 feet (.91 m) above and below the entrance point into the tree. The ability of these fungi to kill the cambium and cause cankers distinguishes them...

Effects of postharvest onion curing parameters on bulb rot caused by Pantoea agglomerans, Pantoea ananatis, and Pantoea allii in storage

USDA-ARS?s Scientific Manuscript database

Crop loss of onion bulbs during storage carries an exceptionally high economic impact since a large portion of the production expenses have been expended before storage occurs. Because of this, it is important to define practices that can reduce onion bulb losses caused by storage rots. This study...

Potassium fertilizer applied immediately after planting had no impact on Douglas-fir seedling mortality caused by laminated root rot on a forested site in Washington State.

Treesearch

Walter G. Thies; Rick G. Kelsey; Douglas J. Westlind; Jeff Madsen

2006-01-01

Phellinus weirii causes laminated root rot (LRR), a major disease affecting growth and survival of Pseudotsuga menziesii (Douglas-fir) and other commercially important conifer species throughout the Pacific Northwest. Increasing tree vigor and resistance to pathogens through application of K fertilizer is a suggested disease...

Control of bull’s-eye rot of apple caused by Neofabraea perennans and Neofabraea kienholzii using pre- and postharvest fungicides

USDA-ARS?s Scientific Manuscript database

Bull’s-eye rot is a major postharvest disease of apple caused by several fungi belonging to the Neofabraea and Phlyctema genera. Chemical control of these fungi is a crucial component of disease management for apples that are conventionally grown. The efficacy of several pre-harvest and postharvest ...

Interactions between cranberries and fungi: the proposed function of organic acids in virulence suppression of fruit rot fungi

PubMed Central

Tadych, Mariusz; Vorsa, Nicholi; Wang, Yifei; Bergen, Marshall S.; Johnson-Cicalese, Jennifer; Polashock, James J.; White, James F.

2015-01-01

Cranberry fruit are a rich source of bioactive compounds that may function as constitutive or inducible barriers against rot-inducing fungi. The content and composition of these compounds change as the season progresses. Several necrotrophic fungi cause cranberry fruit rot disease complex. These fungi remain mostly asymptomatic until the fruit begins to mature in late August. Temporal fluctuations and quantitative differences in selected organic acid profiles between fruit of six cranberry genotypes during the growing season were observed. The concentration of benzoic acid in fruit increased while quinic acid decreased throughout fruit development. In general, more rot-resistant genotypes (RR) showed higher levels of benzoic acid early in fruit development and more gradual decline in quinic acid levels than that observed in the more rot-susceptible genotypes. We evaluated antifungal activities of selected cranberry constituents and found that most bioactive compounds either had no effects or stimulated growth or reactive oxygen species (ROS) secretion of four tested cranberry fruit rot fungi, while benzoic acid and quinic acid reduced growth and suppressed secretion of ROS by these fungi. We propose that variation in the levels of ROS suppressive compounds, such as benzoic and quinic acids, may influence virulence by the fruit rot fungi. Selection for crops that maintain high levels of virulence suppressive compounds could yield new disease resistant varieties. This could represent a new strategy for control of disease caused by necrotrophic pathogens that exhibit a latent or endophytic phase. PMID:26322038

Candida pruni sp. nov. is a new yeast species with antagonistic potential against brown rot of peaches.

PubMed

Zhang, Dian-peng; Lu, Cai-ge; Zhang, Tao-tao; Spadaro, Davide; Liu, De-wen; Liu, Wei-cheng

2014-07-01

Brown rot caused by Monilinia spp. is among the most important postharvest diseases of commercially grown stone fruits, and application of antagonistic yeasts to control brown rot is one promising strategy alternative to chemical fungicides. In this research, new yeast strains were isolated and tested for their activity against peach brown rot caused by Monilinia fructicola. Three yeast strains were originally isolated from the surface of plums (cv Chinese Angelino) collected in the north of China. In artificially wounded inoculation tests, the yeast reduced the brown rot incidence to 20 %. The population of the yeast within inoculated wounds on peaches significantly increased at 25 °C from an initial level of 5.0×10(6) to 4.45×10(7) CFU per wound after 1 day. The antagonistic strains were belonging to a new species of the genus Candida by sequence comparisons of 26 S rDNA D1/D2 domain and internal transcribed spacer region. The strains are most closely related to C. asparagi, C. musae and C. fructus on the basis of the phylogenetic trees based on the D1/D2 region of 26S rDNA. However, the strains are notably different from C. asparagi, C. musae and C. fructus, in morphological and physiological characteristics. Therefore, the name Candida pruni is proposed for the novel species, with sp-Quan (=CBS12814T=KCTC 27526T=GCMC 6582T) as the type strain. Our study showed that Candida pruni is a novel yeast species with potential biocontrol against brown rot caused by M. fructicola on peaches.

[Research on bacteria microecology in root rot rhizosphere soil of Coptis chinensis produced in Shizhu city].

PubMed

Song, Xu-Hong; Wang, Yu; Li, Long-Yun; Tan, Jun

2017-04-01

Illumina Hiseq 2500 high-throughput sequencing platform was used to study the bacteria richness and diversity, the soil enzyme activities, nutrients in unplanted soil, root-rot and healthy rhizophere soil of Coptis chinensis for deeply discussing the mechanism of the root-rot of C. chinensis. The high-throughput sequencing result showed that the artificial cultivation effected the bacteria community richness and diversity. The bacteria community richness in healthy and diseased rhizosphere soil showed significant lower than that of in unplanted soil (P<0.05) and declined bacteria diversity. The bacteria community richness in root-rot rhizosphere soil increased significantly than that of health and unplanted soil and the diversity was lower significant than that of unplanted soil (P<0.05). The results of soil nutrients and enzyme activities detected that the pH value, available phosphorus and urease activity decreased and the sucrase activity increased significantly (P<0.05). The content of organic carbon and alkaline hydrolysis nitrogen the catalase and urease activity in root rot soil samples was significantly lower than that of healthy soil samples (P<0.05). However, the contents of available phosphorus and available potassium were significantly in root-rot sample higher than that of healthy soil samples (P<0.05). Comprehensive analysis showed that the artificial cultivation declined the bacteria community richness and diversity. The bacteria community richness decreased significantly and the decreased diversity may be the cause of the root-rot. Meanwhile, the decrease of carbon and the catalase activity may be another cause of the root-rot in C. chinensis produced in Shizhu city, Chongqing province. Copyright© by the Chinese Pharmaceutical Association.

Occurrence of Internal Stipe Necrosis of Cultivated Mushrooms (Agaricus bisporus) Caused by Ewingella americana in Korea

PubMed Central

Jhune, Chang-Sung; Cheong, Jong-Chun; Yun, Hyung-Sik; Cho, Weon-Dae

2009-01-01

The internal stipe necrosis of cultivated mushrooms (Agaricus bisporus) is caused by the bacterium Ewingella americana, a species of the Enterobacteriaceae. Recently, Ewingella americana was isolated from cultivated white button mushrooms in Korea evidencing symptoms of internal stipe browning. Its symptoms are visible only at harvest, and appear as a variable browning reaction in the center of the stipes. From these lesions, we isolated one bacterial strain (designated CH4). Inoculation of the bacterial isolate into mushroom sporocarps yielded the characteristic browning symptoms that were distinguishable from those of the bacterial soft rot that is well known to mushroom growers. The results of Gram stain, flagellal staining, and biochemical tests identified these isolates as E. americana. This was verified by pathogenicity, physiological and biochemical characteristics, and the results of an analysis of the 16S rRNA gene sequences and the fatty acids profile. This is the first report of the isolation of E. americana from cultivated white button mushrooms in Korea. PMID:23983509

Studies in neotropical polypores. 11, Antrodia aurantia, a new species from the Dominican Republic, Greater Antilles

Treesearch

D. Jean Lodge; Leif Ryvarden; Omar Paino Perdomo-Sanchez

2001-01-01

Antrodia aurantia Lodge, Ryvarden & Perdomo-Sanchez is described as new. It has bright orange resupinate basidiomes that lack rhizomorphs and has pores that are deep, soft, large, and angular to sinuous; it is associated with a brown rot on Pinus occidentalis. A key to all American Antrodia and Diplomitoporus species is provided.

Wood decay by Chlorociboria aeruginascens (Nyl.) Kanouse (Helotiales, Leotiaceae) and associated basidiomycete fungi

Treesearch

Dana L. Richter; Jessie A. Glaeser

2015-01-01

Two isolates of Chlorociboria aeruginascens (Nyl.) Kanouse incubated axenically on aspen wood blocks resulted in 18% and 32% mass loss after 134 wks (2 yrs 8 mo). Aspen wood decayed by C. aeruginascens contained cavities in the S2 layer of the secondary cell wall, similar to Type I soft rot attack, as well as erosion troughs and...

Regulation of Pectate Lyase Synthesis in Pseudomonas fluorescens and Erwinia carotovora

PubMed Central

Zucker, Milton; Hankin, Lester

1970-01-01

Inducible synthesis of extracellular pectate lyase occurs in Erwinia carotovora, a bacterial soft-rot pathogen of plants, and, to a lesser extent, in a nonpathogenic isolate of Pseudomonas fluorescens. A combination of pectin and a heat-labile factor in fresh potato tissue or acetone powders of the tissue provided the best carbon source for induction. Yields of inducible pectate lyase were much greater than those usually reported. The pathogen, but not the saprophyte, produced a small amount of constitutive enzyme when grown on glucose. The relatively low level or absence of constitutive synthesis in these bacteria did not result from catabolite repression. Attempts were made to relieve any existing catabolite repression by restricting growth through slow feeding of glucose or by growing the organisms on glycerol. These conditions did not significantly alter the differential rate of lyase synthesis compared with changes observed in the presence of inducers. Previous growth history did not affect induction in the pathogen. However, P. fluorescens previously cultured on glucose required 10 to 20 generations of growth on inducing medium before appreciable lyase synthesis occurred. Differences between the pathogen and nonpathogen suggest that regulation of pectate lyase synthesis is related to pathogenicity of soft-rot bacteria. PMID:5473883

Grapevine bunch rots: impacts on wine composition, quality, and potential procedures for the removal of wine faults.

PubMed

Steel, Christopher C; Blackman, John W; Schmidtke, Leigh M

2013-06-05

Bunch rot of grape berries causes economic loss to grape and wine production worldwide. The organisms responsible are largely filamentous fungi, the most common of these being Botrytis cinerea (gray mold); however, there are a range of other fungi responsible for the rotting of grapes such as Aspergillus spp., Penicillium spp., and fungi found in subtropical climates (e.g., Colletotrichum spp. (ripe rot) and Greeneria uvicola (bitter rot)). A further group more commonly associated with diseases of the vegetative tissues of the vine can also infect grape berries (e.g., Botryosphaeriaceae, Phomopsis viticola ). The impact these fungi have on wine quality is poorly understood as are remedial practices in the winery to minimize wine faults. Compounds found in bunch rot affected grapes and wine are typically described as having mushroom, earthy odors and include geosmin, 2-methylisoborneol, 1-octen-3-ol, 2-octen-1-ol, fenchol, and fenchone. This review examines the current state of knowledge about bunch rot of grapes and how this plant disease complex affects wine chemistry. Current wine industry practices to minimize wine faults and gaps in our understanding of how grape bunch rot diseases affect wine production and quality are also identified.

Theoretical studies on leaky-SAW properties influenced by layers on anisotropic piezoelectric crystals.

PubMed

Wallner, P; Ruile, W; Weigel, R

2000-01-01

Theoretical studies on the behavior of leaky-SAW (LSAW) properties in layered structures were performed. For these calculations rotYX LiTaO (3) and rotYX LiNbO(3) LSAW crystal cuts were used, assuming different layer materials. For LSAWs both the velocity and the inherent loss due to bulk wave emission into the substrate are strongly influenced by distinct layer parameters. As a result, these layer properties like elastic constants or thickness have shown a strong influence on the crystal cut angle of minimum LSAW loss. Moreover, for soft and stiff layer materials, a different shift of the LSAW loss minimum can occur. Therefore, using double-layer structures, the shift of the LSAW loss minimum can be influenced by appropriate chosen layers and ratios.

The effect of CaCl2 on growth rate, wood decay and oxalic acid accumulation in Serpula lacrymans and related brown-rot fungi

Treesearch

Anne Christine Steenkjaer Hastrup; Bo Jensen; Carol Clausen; Frederick Green

2006-01-01

The dry rot fungus, Serpula lacrymans, is one of the most destructive copper-tolerant fungi causing timber decay in buildings in temperate regions. Calcium and oxalic acid have been shown to play important roles in the mechanism of wood decay. The effect of calcium on growth and decay was evaluated for 12 strains of S. lacrymans and compared to five brown-rot fungi....

Detecting cotton boll rot with an electronic nose

USDA-ARS?s Scientific Manuscript database

South Carolina Boll Rot is an emerging disease of cotton, Gossypium hirsutum L., caused by the opportunistic bacteria, Pantoea agglomerans (Ewing and Fife). Unlike typical fungal diseases, bolls infected with P. agglomerans continue to appear normal externally, complicating early and rapid detectio...

Assessment of Injuries Caused by Anastrepha fraterculus (Wied.) (Diptera: Tephritidae) on the Incidence of Bunch Rot Diseases in Table Grape.

PubMed

Machota, R; Bortoli, L C; Cavalcanti, F R; Botton, M; Grützmacher, A D

2016-08-01

Anastrepha fraterculus (Wied.) is the main insect pest of table grapes (Vitis vinifera) in the Southern Region of Brazil. In this study, we aimed to investigate the effect of fruit puncturing by adult females and larval infestation by A. fraterculus on the occurrence of bunch rot disease in the grape (cultivar "Itália") by evaluating grapes (a) punctured for oviposition by females of A. fraterculus, sterilized in laboratory with novaluron (40 mg L(-1)) and further spray-inoculated separately with Botrytis cinerea (1 × 10(6) conidia mL(-1)), Glomerella cingulata (1 × 10(6) conidia mL(-1)), and bacteria and yeast that cause sour rot (1 × 10(5) cells mL(-1)), (b) grapes punctured for oviposition by non-sterilized females with pathogen spraying, (c) grapes with mechanical wounds and pathogen spraying, (d) grapes with no wounds and with pathogen spraying, (e) grapes punctured for oviposition by A. fraterculus chemically sterilized in laboratory with novaluron, (f) grapes punctured for oviposition by A. fraterculus non-sterilized in laboratory with novaluron, (g) grapes with mechanical wounds, and (h) grapes with no sterilization or pathogen spraying. Our data indicated that the mechanical and oviposition wounds caused by A. fraterculus increased the percentage of grapes infected by B. cinerea, G. cingulata, and microorganisms of acid rot. The grape puncturing by A. fraterculus and the mechanical wound allows the penetration of B. cinerea and microorganisms leading to acid rot. We conclude that the fruit fly A. fraterculus may facilitate phytopathogens penetration leading to bunch rots in the table grape Itália.

Visualization of the structural changes in plywood and gypsum board during the growth of Chaetomium globosum and Stachybotrys chartarum.

PubMed

Lewinska, Anna M; Hoof, Jakob B; Peuhkuri, Ruut H; Rode, Carsten; Lilje, Osu; Foley, Matthew; Trimby, Patrick; Andersen, Birgitte

2016-10-01

Fungal growth in indoor environments is associated with many negative health effects. Many studies focus on brown- and white-rot fungi and their effect on wood, but there is none that reveals the influence of soft-rot fungi, such as Stachybotrys spp. and Chaetomium spp., on the structure of building materials such as plywood and gypsum wallboard. This study focuses on using micro-computed tomography (microCT) to investigate changes of the structure of plywood and gypsum wallboard during fungal degradation by S. chartarum and C. globosum. Changes in the materials as a result of dampness and fungal growth were determined by measuring porosity and pore shape via microCT. The results show that the composition of the building material influenced the level of penetration by fungi as shown by scanning electron microscopy (SEM). Plywood appeared to be the most affected, with the penetration of moisture and fungi throughout the whole thickness of the sample. Conversely, fungi grew only on the top cardboard in the gypsum wallboard and they did not have significant influence on the gypsum wallboard structure. The majority of the observed changes in gypsum wallboard occurred due to moisture. This paper suggests that the mycelium distribution within building materials and the structural changes, caused by dampness and fungal growth, depend on the type of the material. Copyright © 2016 Elsevier B.V. All rights reserved.

Developmental and Metabolic Plasticity of White-Skinned Grape Berries in Response to Botrytis cinerea during Noble Rot1[OPEN

PubMed Central

Collins, Thomas S.; Vicente, Ariel R.; Doyle, Carolyn L.; Ye, Zirou; Allen, Greg; Heymann, Hildegarde

2015-01-01

Noble rot results from exceptional infections of ripe grape (Vitis vinifera) berries by Botrytis cinerea. Unlike bunch rot, noble rot promotes favorable changes in grape berries and the accumulation of secondary metabolites that enhance wine grape composition. Noble rot-infected berries of cv Sémillon, a white-skinned variety, were collected over 3 years from a commercial vineyard at the same time that fruit were harvested for botrytized wine production. Using an integrated transcriptomics and metabolomics approach, we demonstrate that noble rot alters the metabolism of cv Sémillon berries by inducing biotic and abiotic stress responses as well as ripening processes. During noble rot, B. cinerea induced the expression of key regulators of ripening-associated pathways, some of which are distinctive to the normal ripening of red-skinned cultivars. Enhancement of phenylpropanoid metabolism, characterized by a restricted flux in white-skinned berries, was a common outcome of noble rot and red-skinned berry ripening. Transcript and metabolite analyses together with enzymatic assays determined that the biosynthesis of anthocyanins is a consistent hallmark of noble rot in cv Sémillon berries. The biosynthesis of terpenes and fatty acid aroma precursors also increased during noble rot. We finally characterized the impact of noble rot in botrytized wines. Altogether, the results of this work demonstrated that noble rot causes a major reprogramming of berry development and metabolism. This desirable interaction between a fruit and a fungus stimulates pathways otherwise inactive in white-skinned berries, leading to a greater accumulation of compounds involved in the unique flavor and aroma of botrytized wines. PMID:26450706

Developmental and Metabolic Plasticity of White-Skinned Grape Berries in Response to Botrytis cinerea during Noble Rot.

PubMed

Blanco-Ulate, Barbara; Amrine, Katherine C H; Collins, Thomas S; Rivero, Rosa M; Vicente, Ariel R; Morales-Cruz, Abraham; Doyle, Carolyn L; Ye, Zirou; Allen, Greg; Heymann, Hildegarde; Ebeler, Susan E; Cantu, Dario

2015-12-01

Noble rot results from exceptional infections of ripe grape (Vitis vinifera) berries by Botrytis cinerea. Unlike bunch rot, noble rot promotes favorable changes in grape berries and the accumulation of secondary metabolites that enhance wine grape composition. Noble rot-infected berries of cv Sémillon, a white-skinned variety, were collected over 3 years from a commercial vineyard at the same time that fruit were harvested for botrytized wine production. Using an integrated transcriptomics and metabolomics approach, we demonstrate that noble rot alters the metabolism of cv Sémillon berries by inducing biotic and abiotic stress responses as well as ripening processes. During noble rot, B. cinerea induced the expression of key regulators of ripening-associated pathways, some of which are distinctive to the normal ripening of red-skinned cultivars. Enhancement of phenylpropanoid metabolism, characterized by a restricted flux in white-skinned berries, was a common outcome of noble rot and red-skinned berry ripening. Transcript and metabolite analyses together with enzymatic assays determined that the biosynthesis of anthocyanins is a consistent hallmark of noble rot in cv Sémillon berries. The biosynthesis of terpenes and fatty acid aroma precursors also increased during noble rot. We finally characterized the impact of noble rot in botrytized wines. Altogether, the results of this work demonstrated that noble rot causes a major reprogramming of berry development and metabolism. This desirable interaction between a fruit and a fungus stimulates pathways otherwise inactive in white-skinned berries, leading to a greater accumulation of compounds involved in the unique flavor and aroma of botrytized wines. © 2015 American Society of Plant Biologists. All Rights Reserved.

SWEET PEPPER: ASPECTS OF THE BIOLOGY AND CONTROL OF FUSARIUM FRUIT ROT.

PubMed

O'Neill, T; Mayne, S

2015-01-01

Internal fruit rot of sweet pepper grown in glasshouses has been an increasing problem worldwide since around 2000. In the UK, surveys in 2007 showed infected fruits were present in many crops at levels from 1 to 37%. The disease causes some losses on production nurseries but more importantly also causes rejection by packers and complaints by supermarkets. Losses vary greatly between crops and seasons, and growers are generally unaware a problem may be present until harvest or postharvest. The fruit rot arises through infection of flowers (Yang et al., 2010). Several Fusarium species have been associated with the disease in the UK, notably F. lactis and F. oxysporum. Observations in commercial crops indicate the disease is favoured by high humidity. At present there is no effective method of control. This experimental work aimed to reduce losses to Fusarium internal fruit rot through increased knowledge of factors associated with a high incidence of the disease and use of biofungicides and fungicides to control flower infection.

Targhee Russet: A high yielding dual purpose, long russet potato cultivar having higher protein and vitamin C content and resistance to tuber soft rot

USDA-ARS?s Scientific Manuscript database

Targhee Russet is a dark-skinned russet potato variety with tubers slightly longer than Russet Burbank. It produces higher total and marketable yields than does Russet Burbank at most of the sites it was tested in the western United States. Tuber dormancy is about 58 days shorter than Russet Burba...

Biological pretreatment of corn stover with white-rot fungus for improved enzymatic hydrolysis

USDA-ARS?s Scientific Manuscript database

Biological pretreatment of lignocellulosic biomass by white-rot fungus can represent a low-cost and eco-friendly alternative to harsh physical, chemical or physico-chemical pretreatment methods to facilitate enzymatic hydrolysis. However, fungal pretreatment can cause carbohydrate loss and it is, th...

Pre-Breeding for root rot resistance using root morphology traits

USDA-ARS?s Scientific Manuscript database

Root rot caused by the fungal pathogen Rhizoctonia solani can be a major yield-limiting disease in minimal tillage or direct-seeded cereal production systems. Reduced tillage greatly influences the plant residue retained on the soil surfaces. This retained residue (green bridge) provides increased d...

Resident bacteria of plums and their potential for controlling brown rot after harvest

USDA-ARS?s Scientific Manuscript database

Fruit microflora has been the richest source of antagonists against fruit decays and the active ingredient in all currently available commercial biocontrol products. A comprehensive evaluation of plum bacteria for biocontrol activity against Monilinia fructicola, causing brown rot of stone fruit, w...

The Mitochondrial Genome of Moniliophthora roreri, the frosty pod rot pathogen of cacao

USDA-ARS?s Scientific Manuscript database

Moniliophthora roreri and Moniliophthora perniciosa are closely related basidiomycetes that cause two important diseases in cacao (Theobroma cacao L.): frosty pod rot and the witches' broom disease, respectively. A comparison of the complete mitochondrial genomes of these pathogens shows a high degr...

Host resistance to phytophthora fruit rot in U.S. watermelon plant introductions

USDA-ARS?s Scientific Manuscript database

Phytophthora capsici, distributed worldwide, is an aggressive pathogen with a broad host range, infecting solanaceous, leguminaceous, and cucurbitaceous crops. Phytophthora fruit rot of watermelon (Citrullus lanatus) caused by P. capsici was first reported in the U.S. in 1940. Since then, the dise...

Effects of fungal degradation on the CuO oxidation products of lignin: A controlled laboratory study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hedges, J.I.; Weliky, K.; Devol, A.H.

1988-11-01

Duplicate samples of birch wood were degraded for 0, 4, 8 and 12 weeks by the white-rot fungus, Phlebia tremellosus, and for 12 weeks by 6 other white-rot and brown-rot fungi. P. tremellosus caused progressive weight losses and increased the H/C and O/C of the remnant wood by preferentially degrading the lignin component of the middle lamellae. Total yields of syringyl phenols were decreased 1.5 times as fast as total vanillyl phenol yields. Within both phenol families, aldehyde precursors were degraded faster than precursors of the corresponding ketones, which were obtained in constant proportion to the total phenol yield. Althoughmore » two other white-rot fungi caused similar lignin compositional trends, a fourth white-rot species, Coriolus versicolor, simultaneously eroded all cell wall components and did not concentrate polysaccharides in the remnant wood. The brown-rot fungi also preferentially attacked syringyl structural units, but degraded all phenol precursors at a much slower rate than the white-rotters and did not produce excess vanillic acid. Degradation by P. tremellosus linearly increased the vanillic acid/vanillin ratio, (Ad/Al)v, of the remnant birch wood throughout the 12 week degradation study and exponentially decreased the absolute yields of total vanillyl phenols, total syringyl phenols and the syringyl/vanillyl phenol ratio, S/V. At the highest (Ad/Al)v of 0.50 total yields of syringyl and vanillyl phenols were decreased by 65% and 80%, respectively, with a resulting reduction of 40% in the original S/V. Many of the diagenetically related compositional trends that have been previously reported for lignins in natural environments can be explained by white-rot fungal degradation.« less

Evaluation of common bean (Phaseolus vulgaris) response to charcoal rot

USDA-ARS?s Scientific Manuscript database

Charcoal rot in common beans (Phaseolus vulgaris L.), caused by Macrophomina phaseolina (Tassi) Gold. (Mph), is an endemic disease in the prevailing hot and dry conditions in southern Puerto Rico. This study evaluated the 120 bean genotypes that compose the BASE 120 panel under screenhouse conditio...

Genetic Architecture of Charcoal Rot (Macrophomina phaseolina) Resistance in Soybean Revealed Using a Diverse Panel

USDA-ARS?s Scientific Manuscript database

Charcoal rot disease caused by Macrophomina phaseolina is responsible for significant yield losses in soybean production. Among the methodologies available for controlling this disease, breeding for resistance is the most promising. Progress in breeding efforts has been slow due to the insufficient ...

Effect of Charcoal Rot on Selected Putative Drought Resistant Soybean Genotypes and Yield.

USDA-ARS?s Scientific Manuscript database

Charcoal rot (CR), caused by the fungus Macrophomina phaseolina (Tassi) Goid. is a pervasive disease of economic significance on soybeans ([(Glycine max (L.) Merr.) that is exacerbated when plants are under stress, especially under heat and drought condition. Thus, the objective of this research was...

Screening strawberry plants for anthracnose disease resistance using traditional and molecular techniques

USDA-ARS?s Scientific Manuscript database

Anthracnose is one of the most destructive diseases of strawberry which may cause fruit rot, leaf and petiole lesions, crown rot, wilt, and death. Crop loss due to anthracnose diseases can reach into the millions of dollars. Three species of Colletotrichum are considered causative agents of anthr...

Hymenochaetales: a molecular phylogeny for the hymenochaetoid clade

Treesearch

Karl-Henrik Larsson; Erast Parmasto; Michael Fischer; Ewald Langer; Karen K. Nakasone; Scott A. Redhead

2006-01-01

The hymenochaetoid clade is dominated by wood-decaying species previously classified in the artificial families Corticiaceae, Polyporaceae and Stereaceae. The majority of these species cause a white rot. The polypore Bridgeoporus and several corticioid species with inconspicuous basidiomata live in association with brown-rotted wood, but their nutritional strategy is...

Development of molecular methods to detect Macrophomina phaseolina from strawberry plants and soil

USDA-ARS?s Scientific Manuscript database

Macrophomina phaseolina is a broad-host range fungus that shows some degree of host preference on strawberry, and causes symptoms including charcoal rot and root rot. Recently, this pathogen has impacted strawberry production as fumigation practices have changed, leaving many growers in California a...

Creating prescription maps from historical imagery for site-specific management of cotton root rot

USDA-ARS?s Scientific Manuscript database

Cotton root rot, caused by the soilborne fungus Phymatotrichopsis omnivore, is a severe plant disease that has affected cotton production for over a century. Recent research found that a commercial fungicide, Topguard (flutriafol), was able to control this disease. As a result, Topguard Terra Fungic...

Management of bull’s eye rot using preharvest and postharvest fungicides

USDA-ARS?s Scientific Manuscript database

Neofabraea perennans and N. kienholzii are major causal pathogens of bull’s eye rot in apple in Eastern WA. These fungi cause significant economic loss to the Washington State apple industry and have been listed as quarantine pathogens. Previous experiments indicate that fungicide treatments contain...

Combining fuzzy set theory and nonlinear stretching enhancement for unsupervised classification of cotton root rot

USDA-ARS?s Scientific Manuscript database

Cotton root rot is a destructive disease affecting cotton production. Accurate identification of infected areas within fields is useful for cost-effective control of the disease. The uncertainties caused by various infection stages and newly infected plants make it difficult to achieve accurate clas...

Moniliophthora roreri Genome and Transcriptome

USDA-ARS?s Scientific Manuscript database

Frosty pod rot disease of cacao is one of the most destructive diseases of cacao and at this time is limited to regions in South America and Central America. Frosty pod rot is caused by a fungal pathogen Moniliophthora roreri, a basidiomycete that is closely related to another cacao pathogen that ca...

Heroes and villains: Research identifies harmful and beneficial microbes in nursery soil

USDA-ARS?s Scientific Manuscript database

Phytophthora and Pythium species are common pathogens in nursery systems that can cause rhododendron root rot. Plants with root rot are often stunted, and may wilt and die, thus directly reducing nursery profit. Rhododendrons are an important crop in Pacific Northwest nurseries, but are highly susc...

Culturable bacteria from plum fruit surfaces and their potential for controlling brown rot after harvest

USDA-ARS?s Scientific Manuscript database

Fruit microflora has been the richest source of antagonists against fruit decays and the active ingredient in all currently available commercial biocontrol products. A comprehensive evaluation of plum bacteria for biocontrol activity against Monilinia fructicola, causing brown rot of stone fruit, w...

The influence of formulation on Trichoderma biological activity and frosty pod rot disease management in Theobroma cacao

USDA-ARS?s Scientific Manuscript database

Frosty pod rot (FPR), caused by Moniliophthora roreri is responsible for significant losses in Theobroma cacao. Due to the limited options for FPR management, biological control methods using Trichoderma are being studied. Combinations of three formulations and two Trichoderma isolates were studied ...

Evaluating unsupervised and supervised image classification methods for mapping cotton root rot

USDA-ARS?s Scientific Manuscript database

Cotton root rot, caused by the soilborne fungus Phymatotrichopsis omnivora, is one of the most destructive plant diseases occurring throughout the southwestern United States. This disease has plagued the cotton industry for over a century, but effective practices for its control are still lacking. R...

Evaluating spectral measures derived from airborne multispectral imagery for detecting cotton root rot

USDA-ARS?s Scientific Manuscript database

Cotton root rot, caused by the soilborne fungus Phymatotrichopsis omnivore, is one of the most destructive plant diseases occurring throughout the southwestern United States. This disease has plagued the cotton industry for more than 100 years, but effective practices for its control are still lacki...

Evaluation of Fungal Deterioration in Liquidambar orientalis Mill. heartwood by FT-IR and light microscopy.

Treesearch

Nural Yilgor; Dilek Dogu; Roderquita Moore; Evren Terzi; S. Nami Kartal

2013-01-01

The chemical and morphological changes in heartwood specimens of Liquidambar orientalis Mill. caused by the white-rot fungus Trametes versicolor and the brown-rot fungi Tyromyces palustris and Gloeophyllum trabeum were studied by wet chemistry, FT-IR, GC-MS analyses, and photo-...

Pre-breeding for root rot resistance using root morphology and shoot length.

USDA-ARS?s Scientific Manuscript database

Our goal is to identify new wheat varieties that display field resistance/tolerance to root rot diseases, such as those caused by Rhizoctonia and Pythium. We are tapping into the genetic diversity of ‘synthetic’ hexaploid wheats (genome composition AABBDD), which were generated at CIMMYT by artifici...

Grape Berry Colonization and Biological Control of Botrytis cinerea by Indigenous Vineyard Yeasts

USDA-ARS?s Scientific Manuscript database

Botrytis bunch rot, caused by Botrytis cinerea, is the most important disease of grape berries, especially during transportation and storage. Biological control is a potential means of postharvest management of Botrytis bunch rot. The study was aimed at testing the hypothesis that antagonistic yeast...

Diplodiatoxin, chaetoglobosins, and diplonine associated with a field outbreak of Stenocarpella ear rot in Illinois

USDA-ARS?s Scientific Manuscript database

Stenocarpella maydis causes a fungal dry-rot of maize ears and is associated with diplodiosis, a neuromycotoxicosis in cattle grazing harvested maize fields in southern Africa and Argentina. There have been no reports of Stenocarpella metabolites in maize crop residues. Chemical investigations of S....

Molecular phylogeny of Laetiporus and other brown rot polypore genera in North America

Treesearch

Daniel L. Lindner; Mark T. Banik

2008-01-01

Phylogenetic relationships were investigated among North American species of Laetiporus, Leptoporus, Phaeolus, Pycnoporellus, and Wolfiporia using ITS, nuclear large subunit and mitochondrial small subunit rDNA sequences. Members of these genera have poroid hymenophores, simple septate hyphae and cause brown rots in a variety of...

Effects of fungal degradation on the CuO oxidation products of lignin: A controlled laboratory study

NASA Astrophysics Data System (ADS)

Hedges, John I.; Blanchette, Robert A.; Weliky, Karen; Devol, Allan H.

1988-11-01

Duplicate samples of birch wood were degraded for 0, 4, 8 and 12 weeks by the white-rot fungus, Phlebia tremellosus, and for 12 weeks by 6 other white-rot and brown-rot fungi. P. tremellosus caused progressive weight losses and increased the H/C and O/C of the remnant wood by preferentially degrading the lignin component of the middle lamellae. This fungus increased the absolute (weight loss-corrected) yield of the vanillic acid CuO reaction product above its initial level and exponentially decreased the absolute yields of all other lignin-derived phenols. Total yields of syringyl phenols were decreased 1.5 times as fast as total vanillyl phenol yields. Within both phenol families, aldehyde precursors were degraded faster than precursors of the corresponding ketones, which were obtained in constant proportion to the total phenol yield. Although two other white-rot fungi caused similar lignin compositional trends, a fourth white-rot species, Coriolus versicolor, simultaneously eroded all cell wall components and did not concentrate polysaccharides in the remnant wood. Wood degraded by the three brown-rot fungi exhibited porous cell walls with greatly reduced integrity. The brown-rot fungi also preferentially attacked syringyl structural units, but degraded all phenol precursors at a much slower rate than the white-rotters and did not produce excess vanillic acid. Degradation by P. tremellosus linearly increased the vanillic acid/vanillin ratio, (Ad/Al)v, of the remnant birch wood throughout the 12 week degradation study and exponentially decreased the absolute yields of total vanillyl phenols, total syringyl phenols and the syringyl/vanillyl phenol ratio, S/V. At the highest (Ad/Al)v of 0.50 (12 week samples), total yields of syringyl and vanillyl phenols were decreased by 65% and 80%, respectively, with a resulting reduction of 40% in the original S/V. Many of the diagenetically related compositional trends that have been previously reported for lignins in natural environments can be explained by white-rot fungal degradation.

Onion Thrips (Thysanoptera: Thripidae) Feeding Promotes Infection By Pantoea ananatis in Onion.

PubMed

Grode, Ari; Chen, Shicheng; Walker, Edward D; Szendrei, Zsofia

2017-12-05

Onion thrips, Thrips tabaci Lindeman, is a primary insect pest of onions (Allium cepa) worldwide. Onion thrips cause feeding damage by destroying epidermal tissue. They are also vectors of Pantoea ananatis (Serrano) Mergaert, the bacteria that causes center rot. Onions with center rot develop white streaks with water-soaked margins along the onion leaves, which turn necrotic and lead to bulb rot during storage. The role of thrips feeding on the establishment and progression of bacterial infection in onions has not been investigated. Onions infested with thrips and inoculated with P. ananatis had more necrotic tissue and symptoms were more severe with increasing thrips density. We conducted a fluorescence microscopy study that examined how P. ananatis (expressing a fluorescence protein gene) colonized a control group of onions without thrips in comparison to a test group of onions with thrips. We found that P. ananatis colonized some onions in the control group because of naturally existing wounds in the epidermal tissue but more colonization was found in the thrips infested group because of the increased presence of entry points caused by thrips feeding. Overall, our results demonstrate that wounds caused by thrips feeding facilitate center rot development by providing entry sites for the bacteria into leaf tissue. © The Author(s) 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Comparison of Pratylenchus penetrans Infection and Maladera castanea Feeding on Strawberry Root Rot

PubMed Central

LaMondia, J. A.; Cowles, R. S.

2005-01-01

The interaction of lesion nematodes, black root rot disease caused by Rhizoctonia fragariae, and root damage caused by feeding of the scarab larva, Maladera castanea, was determined in greenhouse studies. Averaged over all experiments after 12 weeks, root weight was reduced 13% by R. fragariae and 20% by M. castanea. The percentage of the root system affected by root rot was increased by inoculation with either R. fragariae (35% more disease) or P. penetrans (50% more disease) but was unaffected by M. castanea. Rhizoctonia fragariae was isolated from 9.2% of the root segments from plants not inoculated with R. fragariae. The percentage of R. fragariae-infected root segments was increased 3.6-fold by inoculation with R. fragariae on rye seeds. The presence of P. penetrans also increased R. fragariae root infection. The type of injury to root systems was important in determining whether roots were invaded by R. fragariae and increased the severity of black root rot. Pratylenchus penetrans increased R. fragariae infection and the severity of black root rot. Traumatic cutting action by Asiatic garden beetle did not increase root infection or root disease by R. fragariae. Both insects and diseases need to be managed to extend the productive life of perennial strawberry plantings. PMID:19262852

Intermittent Fasting Applied in Combination with Rotenone Treatment Exacerbates Dopamine Neurons Degeneration in Mice

PubMed Central

Tatulli, Giuseppe; Mitro, Nico; Cannata, Stefano M.; Audano, Matteo; Caruso, Donatella; D’Arcangelo, Giovanna; Lettieri-Barbato, Daniele; Aquilano, Katia

2018-01-01

Intermittent fasting (IF) was suggested to be a powerful nutritional strategy to prevent the onset of age-related neurodegenerative diseases associated with compromised brain bioenergetics. Whether the application of IF in combination with a mitochondrial insult could buffer the neurodegenerative process has never been explored yet. Herein, we defined the effects of IF in C57BL/6J mice treated once per 24 h with rotenone (Rot) for 28 days. Rot is a neurotoxin that inhibits the mitochondrial complex I and causes dopamine neurons degeneration, thus reproducing the neurodegenerative process observed in Parkinson’s disease (PD). IF (24 h alternate-day fasting) was applied alone or in concomitance with Rot treatment (Rot/IF). IF and Rot/IF groups showed the same degree of weight loss when compared to control and Rot groups. An accelerating rotarod test revealed that only Rot/IF mice have a decreased ability to sustain the test at the higher speeds. Rot/IF group showed a more marked decrease of dopaminergic neurons and increase in alpha-synuclein (α-syn) accumulation with respect to Rot group in the substantia nigra (SN). Through lipidomics and metabolomics analyses, we found that in the SN of Rot/IF mice a significant elevation of excitatory amino acids, inflammatory lysophospholipids and sphingolipids occurred. Collectively, our data suggest that, when applied in combination with neurotoxin exposure, IF does not exert neuroprotective effects but rather exacerbate neuronal death by increasing the levels of excitatory amino acids and inflammatory lipids in association with altered brain membrane composition. PMID:29387000

Intermittent Fasting Applied in Combination with Rotenone Treatment Exacerbates Dopamine Neurons Degeneration in Mice.

PubMed

Tatulli, Giuseppe; Mitro, Nico; Cannata, Stefano M; Audano, Matteo; Caruso, Donatella; D'Arcangelo, Giovanna; Lettieri-Barbato, Daniele; Aquilano, Katia

2018-01-01

Intermittent fasting (IF) was suggested to be a powerful nutritional strategy to prevent the onset of age-related neurodegenerative diseases associated with compromised brain bioenergetics. Whether the application of IF in combination with a mitochondrial insult could buffer the neurodegenerative process has never been explored yet. Herein, we defined the effects of IF in C57BL/6J mice treated once per 24 h with rotenone (Rot) for 28 days. Rot is a neurotoxin that inhibits the mitochondrial complex I and causes dopamine neurons degeneration, thus reproducing the neurodegenerative process observed in Parkinson's disease (PD). IF (24 h alternate-day fasting) was applied alone or in concomitance with Rot treatment (Rot/IF). IF and Rot/IF groups showed the same degree of weight loss when compared to control and Rot groups. An accelerating rotarod test revealed that only Rot/IF mice have a decreased ability to sustain the test at the higher speeds. Rot/IF group showed a more marked decrease of dopaminergic neurons and increase in alpha-synuclein (α-syn) accumulation with respect to Rot group in the substantia nigra (SN). Through lipidomics and metabolomics analyses, we found that in the SN of Rot/IF mice a significant elevation of excitatory amino acids, inflammatory lysophospholipids and sphingolipids occurred. Collectively, our data suggest that, when applied in combination with neurotoxin exposure, IF does not exert neuroprotective effects but rather exacerbate neuronal death by increasing the levels of excitatory amino acids and inflammatory lipids in association with altered brain membrane composition.

Molecular mapping of QTLs for resistance to Gibberella ear rot, in corn, caused by Fusarium graminearum.

PubMed

Ali, M Liakat; Taylor, Jeff H; Jie, Liu; Sun, Genlou; William, Manilal; Kasha, Ken J; Reid, Lana M; Pauls, K Peter

2005-06-01

Gibberella ear rot, caused by the fungus Fusarium graminearum Schwabe, is a serious disease of corn (Zea mays) grown in northern climates. Infected corn is lower yielding and contains toxins that are dangerous to livestock and humans. Resistance to ear rot in corn is quantitative, specific to the mode of fungal entry (silk channels or kernel wounds), and highly influenced by the environment. Evaluations of ear rot resistance are complex and subjective; and they need to be repeated over several years. All of these factors have hampered attempts to develop F. graminearum resistant corn varieties. The aim of this study was to identify molecular markers linked to the genes for resistance to Gibberella ear rot. A recombinant inbred (RI) population, produced from a cross between a Gibberella ear rot resistant line (CO387) and a susceptible line (CG62), was field-inoculated and scored for Gibberella ear rot symptoms in the F4, F6, and F7 generations. The distributions of disease scores were continuous, indicating that resistance is probably conditioned by multiple loci. A molecular linkage map, based on segregation in the F5 RI population, contained 162 markers distributed over 10 linkage groups and had a total length of 2237 cM with an average distance between markers of 13.8 cM. Composite interval mapping identified 11 quantitative trait loci (QTLs) for Gibberella ear rot resistance following silk inoculation and 18 QTLs following kernel inoculation in 4 environments that accounted for 6.7%-35% of the total phenotypic variation. Only 2 QTLs (on linkage group 7) were detected in more than 1 test for silk resistance, and only 1 QTL (on linkage group 5) was detected in more than 1 test for kernel resistance, confirming the strong influence of the environment on these traits. The majority of the favorable alleles were derived from the resistant parent (CO387). The germplasm and markers for QTLs with significant phenotypic effects may be useful for marker-assisted selection to incorporate Gibberella ear rot resistance into commercial corn cultivars.

Involvement of phenazines and lipopeptides in interactions between Pseudomonas species and Sclerotium rolfsii, causal agent of stem rot disease on groundnut.

PubMed

Le, C N; Kruijt, M; Raaijmakers, J M

2012-02-01

To determine the role of phenazines (PHZ) and lipopeptide surfactants (LPs) produced by Pseudomonas in suppression of stem rot disease of groundnut, caused by the fungal pathogen Sclerotium rolfsii. In vitro assays showed that PHZ-producing Pseudomonas chlororaphis strain Phz24 significantly inhibited hyphal growth of S. rolfsii and suppressed stem rot disease of groundnut under field conditions. Biosynthesis and regulatory mutants of Phz24 deficient in PHZ production were less effective in pathogen suppression. Pseudomonas strains SS101, SBW25 and 267, producing viscosin or putisolvin-like LPs, only marginally inhibited hyphal growth of S. rolfsii and did not suppress stem rot disease. In contrast, Pseudomonas strain SH-C52, producing the chlorinated LP thanamycin, inhibited hyphal growth of S. rolfsii and significantly reduced stem rot disease of groundnut in nethouse and field experiments, whereas its thanamycin-deficient mutant was less effective. Phenazines and specific lipopeptides play an important role in suppression of stem rot disease of groundnut by root-colonizing Pseudomonas strains. Pseudomonas strains Phz24 and SH-C52 showed significant control of stem rot disease. Treatment of seeds or soil with these strains provides a promising supplementary strategy to control stem rot disease of groundnut. © 2011 The Authors. Journal of Applied Microbiology © 2011 The Society for Applied Microbiology.

Incorporation of brassica seed meal soil amendment and wheat cultivation for control of macrophomina phaseolina in strawberry

USDA-ARS?s Scientific Manuscript database

Macrophomina phaseolina is the cause of charcoal rot, a disease of emerging importance in strawberry production systems. Brassicaceae seed meals (SM) and prior cultivation of soils with wheat, were evaluated for the capacity to suppress charcoal rot of strawberry and to determine the relative contri...

First report of Gliocephalotrichum bulbilium and G. simplex causing fruit rot of rambutan in Puerto Rico

USDA-ARS?s Scientific Manuscript database

Worldwide, significant post-harvest disease losses of rambutan (Nephelium lappaceum L.) have been reported and several pathogens have been associated with fruit rot. Even though rambutan was introduced to Puerto Rico in 1927, it was not until 1998 that commercial farms were established in the wester...

A novel penicillium sp. causes rot in stored sugar beet roots in Idaho

USDA-ARS?s Scientific Manuscript database

Penicillium vulpinum along with a number of other fungi can lead to the rot of stored sugar beet roots. However, Penicillium isolates associated with necrotic lesions on roots from a recent sugar beet storage study were determined to be different from P. vulpinum and other recognized Penicillium sp...

Relationship between piercing-sucking insect control and internal lint and seed rot in Southeastern cotton (Gossypium hirsutum)

USDA-ARS?s Scientific Manuscript database

In 1999 crop consultants scouting for stink bugs (several Hemiptera spp.) in South Carolina discovered a formerly unobserved seed rot of cotton that caused yield losses ranging from 10 to 15% in certain fields. The same symptoms were subsequently reported in fields throughout the southeastern Cotto...

Phytophthora megakarya, a causal agent of black pod rot in Africa

USDA-ARS?s Scientific Manuscript database

In most parts of the world where Theobroma cacao is grown, Phytophthora palmivora is the major concern for causing black pod rot (BPR). Phytophthora megakarya, on the other hand, occurs only in Africa, but represents a major threat to cacao production, the countries of West Africa being the largest ...

Acid and neutral trehalase activities in mutants of the corn rot fungus Fusarium verticillioides

USDA-ARS?s Scientific Manuscript database

Fusarium verticillioides is a fungal pathogen known to cause corn rot and other plant diseases and to contaminate grain with toxic metabolites. We are characterizing trehalose metabolism in F. verticillioides with the hope that this pathway might serve as a target for controlling Fusarium disease. T...

Characterization of blue mold Penicillium species isolated from stored fruits using multiple highly conserved loci

USDA-ARS?s Scientific Manuscript database

Penicillium is a large genus of common molds with over 400 described species; however, identification of individual species is difficult, including for those species that cause postharvest rots. In this study, blue rot fungi from stored apples and pears were isolated from a variety of hosts, locatio...

First report of Phytophthora root rot, caused by Phytophthora cryptogea, on spinach in California

USDA-ARS?s Scientific Manuscript database

In 2006 and 2007, commercially grown spinach (Spinacia oleracea) in California’s coastal Salinas Valley (Monterey County) was affected by an unreported root rot disease. Disease was limited to patches along the edges of fields. Affected plants were stunted with chlorotic older leaves. As disease pro...

Kimberly sugar beet germplasm evaluated for rhizomania and storage rot resistance in Idaho, 2015

USDA-ARS?s Scientific Manuscript database

Rhizomania caused by Beet necrotic yellow vein virus (BNYVV) and storage losses are serious sugar beet production problems. To identify sugar beet germplasm lines with resistance to BNYVV and storage rots, 11germplasm lines from the USDA-ARS Kimberly sugar beet program were screened. The lines wer...

Management of bull’s-eye rot of apple using pre- and postharvest fungicides

USDA-ARS?s Scientific Manuscript database

Bull’s-eye rot caused by Cryptosporiopsis kienholzii, Neofabraea alba, N. malicorticis and N. perennans is a common postharvest disease of apple and pear in the US Pacific Northwest. Fruit infection by these causal fungi occurs in the orchard and is latent at harvest. A primary practice for control ...

Responses to recurrent index selection for reduced fusarium ear rot and lodging and for increased yield in maize

USDA-ARS?s Scientific Manuscript database

Fusarium ear rot caused by the pathogen Fusarium verticillioides (Sacc.) Nirenberg damages maize (Zea mays L.) grain production and is associated with contamination of grain by fumonisin, a mycotoxin harmful to both humans and animals. Recurrent selection may be an effective way to combine improveme...

Laminated root rot in western North America.

Treesearch

Walter G. Thies; Rona N. Sturrock

1995-01-01

Laminated root rot, caused by Phellinus weirii (Murr.) Gilb., is a serious root disease affecting Douglas-fir and other commercially important species of conifers in northwestern North America. This report gives an overview of the dis-ease as it occurs in the Pacific Northwest in Canada and the United States. Information on recognizing crown...

Bioactive metabolites from Stenocarpella maydis, a stalk and ear rot pathogen of maize

USDA-ARS?s Scientific Manuscript database

Stenocarpella maydis is a fungal pathogen of major importance that causes a dry-rot of maize ears and is associated with a neuromycotoxicosis in cattle grazing harvested maize fields in southern Africa and Argentina. In an effort to investigate the potential roles of S. maydis metabolites in the fun...

Characterizing and mapping resistance in synthetic-derived wheat to Rhizoctonia root rot in a green bridge environment

USDA-ARS?s Scientific Manuscript database

Root rot caused by Rhizoctonia species is an economically important soilborne disease of spring planted wheat in growing regions of the Pacific Northwest (PNW). The main method of controlling the disease currently is through tillage, which deters farmers from adopting the benefits of minimal tillage...

Wilt, crown, and root rot of common rose mallow (Hibiscus moscheutos) caused by a novel Fusarium sp

USDA-ARS?s Scientific Manuscript database

A new crown and root rot disease of landscape plantings of the malvaceous ornamental common rose mallow (Hibiscus moscheutos) was first detected in Washington State in 2012. The main objectives of this study were to complete Koch's postulates, document the disease sypmtoms photographically, and iden...

Evaluation of Intego Solo (ethaboxam) for management of metalaxyl-resistant Pythium spp. in chickpea

USDA-ARS?s Scientific Manuscript database

Pythium damping-off and Pythium root rot, caused by numerous species of Pythium, can be a major limiting factor in the emergence and stand establishment of chickpea. Pythium spp. infect the germinating seed and seedling, often resulting in seed rot and subsequent damping-off in northern Idaho. Cur...

Chitosan and oligochitosan enhance ginger (Zingiber officinale Roscoe) resistance to rhizome rot caused by Fusarium oxysporum in storage.

PubMed

Liu, Yiqing; Wisniewski, Michael; Kennedy, John F; Jiang, Yusong; Tang, Jianmin; Liu, Jia

2016-10-20

The ability of chitosan and oligochitosan to enhance ginger (Zingiber officinale) resistance to rhizome rot caused by Fusarium oxysporum in storage was investigated. Both chitosan and oligochitosan at 1 and 5g/L significantly inhibited rhizome rot, with the best control at 5g/L. Chitosan and oligochitosan applied at 5g/L also reduced weight loss, measured as a decrease in fresh weight, but did not affect soluble solids content or titratable acidity of rhizomes. The two compounds applied at 5g/L induced β-1,3-glucanase and phenylalanine ammonia-lyase enzyme activity and the transcript levels of their coding genes, as well as the total phenolic compounds in rhizome tissues. Therefore, the ability of chitosan and oligochitosan to reduce rot in stored rhizomes may be associated with their ability to induce defense responses in ginger. These results have practical implications for the application of chitosan and oligochitosan to harvested ginger rhizomes to reduce postharvest losses. Copyright © 2016 Elsevier Ltd. All rights reserved.

Survey of Basal Stem Rot Disease on Oil Palms (Elaeis guineensis Jacq.) in Kebun Bukit Kijang,North Sumatera, Indonesia

NASA Astrophysics Data System (ADS)

Lisnawita; Hanum, H.; Tantawi, A. R.

2016-08-01

Basal stem rot disease caused by Ganoderma sp. is a significant disease on oil palm plantations in Indonesia, especially in North Sumatera. Currently, the pathogen does not only attack the plants that have produced (old plants) but also attacks the plants that have not produced in the first generation yet. A survey of the distribution of the basal stem rot disease in the plantation of the community has been completed in order to illustrate the distribution and the incidence of the basal stem rot disease in 5 locations of the oil palm plantation of the community in Desa Bukit Kijang, Region of Asahan, North Sumatera, Indonesia. From the research, it is revealed that the basal stem rot disease has spread to all of the observed locations with the level of disease incidence between 0.71% in Kebun Bukit Kijang 3 to 50% in the 17 years old oil palm in Kebun Bukit Kijang 4 and Bukit Kijang 5. The observable symptoms of the basal stem rot disease are chlorotic leaves, the appearance of fruiting body, collapsed plants, and the existence of holes on the basal stem. The incidence of basal stem rot disease is higher on land due to a high sand content (>50%).

Newly Isolated Bacteriophages from the Podoviridae, Siphoviridae, and Myoviridae Families Have Variable Effects on Putative Novel Dickeya spp.

PubMed

Alič, Špela; Naglič, Tina; Tušek-Žnidarič, Magda; Ravnikar, Maja; Rački, Nejc; Peterka, Matjaž; Dreo, Tanja

2017-01-01

Soft rot pathogenic bacteria from the genus Dickeya cause severe economic losses in orchid nurseries worldwide, and there is no effective control currently available. In the last decade, the genus Dickeya has undergone multiple changes as multiple new taxa have been described, and just recently a new putative Dickeya species was reported. This study reports the isolation of three bacteriophages active against putative novel Dickeya spp. isolates from commercially produced infected orchids that show variable host-range profiles. Bacteriophages were isolated through enrichment from Dickeya -infected orchid tissue. Convective interaction media monolith chromatography was used to isolate bacteriophages from wastewaters, demonstrating its suitability for the isolation of infective bacteriophages from natural sources. Based on bacteriophage morphology, all isolated bacteriophages were classified as being in the order Caudovirales , belonging to three different families, Podoviridae , Myoviridae , and Siphoviridae . The presence of three different groups of bacteriophages was confirmed by analyzing the bacteriophage specificity of bacterial hosts, restriction fragment length polymorphism and plaque morphology. Bacteriophage BF25/12, the first reported Podoviridae bacteriophage effective against Dickeya spp., was selected for further characterization. Its genome sequence determined by next-generation sequencing showed limited similarity to other characterized Podoviridae bacteriophages. Interactions among the bacteriophages and Dickeya spp. were examined using transmission electron microscopy, which revealed degradation of electron-dense granules in response to bacteriophage infection in some Dickeya strains. The temperature stability of the chosen Podoviridae bacteriophage monitored over 1 year showed a substantial decrease in the survival of bacteriophages stored at -20°C over longer periods. It showed susceptibility to low pH and UV radiation but was stable in neutral and alkaline pH. Furthermore, the stability of the tested bacteriophage was also connected to the incubation medium and bacteriophage concentration at certain pH values. Finally, the emergence of bacteriophage-resistant bacterial colonies is highly connected to the concentration of bacteriophages in the bacterial environment. This is the first report on bacteriophages against Dickeya from the Podoviridae family to expand on potential bacteriophages to include in bacteriophage cocktails as biocontrol agents. Some of these bacteriophage isolates also showed activity against Dickeya solani , an aggressive strain that causes the soft rot of potatoes, which indicates their broad potential as biocontrol agents.

Newly Isolated Bacteriophages from the Podoviridae, Siphoviridae, and Myoviridae Families Have Variable Effects on Putative Novel Dickeya spp.

PubMed Central

Alič, Špela; Naglič, Tina; Tušek-Žnidarič, Magda; Ravnikar, Maja; Rački, Nejc; Peterka, Matjaž; Dreo, Tanja

2017-01-01

Soft rot pathogenic bacteria from the genus Dickeya cause severe economic losses in orchid nurseries worldwide, and there is no effective control currently available. In the last decade, the genus Dickeya has undergone multiple changes as multiple new taxa have been described, and just recently a new putative Dickeya species was reported. This study reports the isolation of three bacteriophages active against putative novel Dickeya spp. isolates from commercially produced infected orchids that show variable host-range profiles. Bacteriophages were isolated through enrichment from Dickeya-infected orchid tissue. Convective interaction media monolith chromatography was used to isolate bacteriophages from wastewaters, demonstrating its suitability for the isolation of infective bacteriophages from natural sources. Based on bacteriophage morphology, all isolated bacteriophages were classified as being in the order Caudovirales, belonging to three different families, Podoviridae, Myoviridae, and Siphoviridae. The presence of three different groups of bacteriophages was confirmed by analyzing the bacteriophage specificity of bacterial hosts, restriction fragment length polymorphism and plaque morphology. Bacteriophage BF25/12, the first reported Podoviridae bacteriophage effective against Dickeya spp., was selected for further characterization. Its genome sequence determined by next-generation sequencing showed limited similarity to other characterized Podoviridae bacteriophages. Interactions among the bacteriophages and Dickeya spp. were examined using transmission electron microscopy, which revealed degradation of electron-dense granules in response to bacteriophage infection in some Dickeya strains. The temperature stability of the chosen Podoviridae bacteriophage monitored over 1 year showed a substantial decrease in the survival of bacteriophages stored at -20°C over longer periods. It showed susceptibility to low pH and UV radiation but was stable in neutral and alkaline pH. Furthermore, the stability of the tested bacteriophage was also connected to the incubation medium and bacteriophage concentration at certain pH values. Finally, the emergence of bacteriophage-resistant bacterial colonies is highly connected to the concentration of bacteriophages in the bacterial environment. This is the first report on bacteriophages against Dickeya from the Podoviridae family to expand on potential bacteriophages to include in bacteriophage cocktails as biocontrol agents. Some of these bacteriophage isolates also showed activity against Dickeya solani, an aggressive strain that causes the soft rot of potatoes, which indicates their broad potential as biocontrol agents. PMID:29033917

Bacterial Diseases of Bananas and Enset: Current State of Knowledge and Integrated Approaches Toward Sustainable Management

PubMed Central

Blomme, Guy; Dita, Miguel; Jacobsen, Kim Sarah; Pérez Vicente, Luis; Molina, Agustin; Ocimati, Walter; Poussier, Stephane; Prior, Philippe

2017-01-01

Bacterial diseases of bananas and enset have not received, until recently, an equal amount of attention compared to other major threats to banana production such as the fungal diseases black leaf streak (Mycosphaerella fijiensis) and Fusarium wilt (Fusarium oxysporum f. sp. cubense). However, bacteria cause significant impacts on bananas globally and management practices are not always well known or adopted by farmers. Bacterial diseases in bananas and enset can be divided into three groups: (1) Ralstonia-associated diseases (Moko/Bugtok disease caused by Ralstonia solanacearum and banana blood disease caused by R. syzygii subsp. celebesensis); (2) Xanthomonas wilt of banana and enset, caused by Xanthomonas campestris pv. musacearum and (3) Erwinia-associated diseases (bacterial head rot or tip-over disease Erwinia carotovora ssp. carotovora and E. chrysanthemi), bacterial rhizome and pseudostem wet rot (Dickeya paradisiaca formerly E. chrysanthemi pv. paradisiaca). Other bacterial diseases of less widespread importance include: bacterial wilt of abaca, Javanese vascular wilt and bacterial fingertip rot (probably caused by Ralstonia spp., unconfirmed). This review describes global distribution, symptoms, pathogenic diversity, epidemiology and the state of the art for sustainable disease management of the major bacterial wilts currently affecting banana and enset. PMID:28785275

Repeated Structures Found After the Solar Maximum in the Butterfly Diagrams of Coronal Holes

NASA Astrophysics Data System (ADS)

Hofer, M. Y.; Storini, M.

2003-09-01

The influence of the solar cycle evolution on the coronal hole space-time distribution is well known, for polar as well as for equatorial isolated sources of high speed solar wind. Among them the long-lived coronal holes occurrence from the sunspot cycle 21 on is investigated, using the coronal hole catalogue based on HeI (1083 nm) observations (Sanchez-Ibarra and Barraza-Paredes). In at least these two solar cycles (n. 21 and n. 22) a similar structure in the latitude-time diagram of coronal holes is found. The area occurs shortly after the solar maximum at around ~35° heliolatitude and consists of over several Carrington Rotations stable coronal holes (>5 Carr. Rot.s). The diagonal disappears 2-3 years later at the helioequator. Furthermore, the analysis results in a close relation between long-lived isolated coronal holes and the soft X-class flares.

21 CFR 522.1662a - Oxytetracycline hydrochloride injection.

Code of Federal Regulations, 2011 CFR

2011-04-01

... (scours) (E. coli), foot-rot (Spherophorus necrophorus), diphtheria (Spherophorus necrophorus), wooden...) caused by Escherichia coli, wooden tongue caused by Actinobacillus lignieresi, leptospirosis caused by...) caused by Escherichia coli, pneumonia caused by Pasteurella multocida, and leptospirosis caused by...

21 CFR 522.1662a - Oxytetracycline hydrochloride injection.

Code of Federal Regulations, 2010 CFR

2010-04-01

... (scours) (E. coli), foot-rot (Spherophorus necrophorus), diphtheria (Spherophorus necrophorus), wooden...) caused by Escherichia coli, wooden tongue caused by Actinobacillus lignieresi, leptospirosis caused by...) caused by Escherichia coli, pneumonia caused by Pasteurella multocida, and leptospirosis caused by...

Effect of anaerobic soil disinfestation and mustard seed meal for control of charcoal rot in California strawberries

USDA-ARS?s Scientific Manuscript database

Anaerobic soil disinfestation (ASD) and mustard seed meal (MSM) appear to be promising non-fumigant alternatives for soilborne disease control. However studies of their effect on charcoal rot caused by Macrophomina phaseolina in California strawberry are limited. ASD with rice bran 20 t ha-1 (ASD-RB...

Registration of DT99-16864 soybean germplasm line with moderate resistance to charcoal rot [Macrophomina phaseolina (Tassi) Goid

USDA-ARS?s Scientific Manuscript database

Charcoal rot, caused by Macrophomina phaseolina (Tassi) Goidanich, is a disease that is a world-wide problem in soybean production for which no highly resistant cultivars are currently available. Soybean germplasm line DT99-16864, a maturity group V line, was developed by the U.S. Department of Ag...

Laminated Root Rot of Western Conifers

Treesearch

E.E. Nelson; N.E. Martin; R.E. Williams

1981-01-01

Laminated root rot is caused by the native fungus Phellinus weirii (Murr.) Gilb. It occurs throughout the Northwestern United States and in southern British Columbia, Canada. The disease has also been reported in Japan and Manchuria. In the United States, the pathogen is most destructive in pure Douglas-fir stands west of the crest of the Cascade Range in Washington...

Fine mapping of resistance genes from five brown stem rot resistance sources in soybean

USDA-ARS?s Scientific Manuscript database

Brown stem rot (BSR) of soybean [Glycine max (L.) Merr.] caused by Cadophora gregata (Allington & Chamb.) T.C. Harr. & McNew, can be controlled effectively with genetic host resistance. Three BSR resistance genes Rbs1, Rbs2, and Rbs3, have been identified and mapped to a large region on chromosome 1...

First report of anthracnose fruit rot of blueberry caused by Colletotrichum fioriniae in New Jersey

USDA-ARS?s Scientific Manuscript database

Anthracnose fruit rot is the most important disease of blueberry in New Jersey. Most fungicide applications in New Jersey and other blueberry growing regions is for the control of this disease. The causal agent of this disease has been reported to be Colletotrichum acutatum and other species in the ...

SNP discovery and QTL mapping of Sclerotinia basal stalk rot resistance in sunflower using genotyping-by-sequencing (GBS)

USDA-ARS?s Scientific Manuscript database

Basal stalk rot (BSR) caused by the ascomycete fungus Sclerotinia sclerotiorum (Lib.) de Bary is a serious disease of sunflower (Helianthus annuus L.) in the cool and humid production areas of the world. Quantitative trait loci (QTL) for BSR resistance were identified in a sunflower recombinant inbr...

Current Research on Wood Decay in the USDA Forest Service

Treesearch

Harold H. Burdsall Jr.

1991-01-01

The Forest Service's research on decay fungi and decay caused by fungi is done mainly in two research work units at the Forest Products Laboratory. One unit, the Center for Forest Mycology Research, performs biosystematic research on root-rot and products-rot fungi in the genera Armillaria, Phellinus, and Phlebia and maintains the culture collection supporting...

Pathogenicity, fungicide resistance, and genetic variability of Phytophthora rubi isolates from raspberry (Rubus idaeus) in the Western United States

USDA-ARS?s Scientific Manuscript database

Root rot of raspberry (Rubus idaeus), thought to be primarily caused by Phytophthora rubi, is an economically important disease in the western United States. The objectives of this study were to determine which Phytophthora species are involved in root rot, examine the efficacy of different isolatio...

Multidimensional NMR analysis reveals truncated lignin structures in wood decayed by the brown rot basidiomycete Postia placenta

Treesearch

Daniel J. Yelle; Dongsheng Wei; John Ralph; Kenneth E. Hammel

2011-01-01

Lignocellulose biodegradation, an essential step in terrestrial carbon cycling, generally involves removal of the recalcitrant lignin barrier that otherwise prevents infiltration by microbial polysaccharide hydrolases. However, fungi that cause brown rot of wood, a major route for biomass recycling in coniferous forests, utilize wood polysaccharides efficiently while...

The role of chemical transport in the brown-rot decay resistance of modified wood

Treesearch

Samuel Zelinka; R. Ringman; A. Pilgard; E. E. Thybring; Joseph Jakes; K. Richter

2016-01-01

Chemical modification of wood increases decay resistance but the exact mechanisms remain poorly understood. Recently, Ringman and coauthors examined established theories addressing why modified wood has increased decay resistance and concluded that the most probable cause of inhibition and/or delay of initiation of brown-rot decay is lowering the equilibrium moisture...

Efficacy of management tools for control of Pythium root rot of Douglas-fir seedlings, 2013

USDA-ARS?s Scientific Manuscript database

This study was conducted as part of the IR-4 Ornamental Horticulture program to evaluate fungicides and biopesticides for management of root, crown and stem rots of ornamental plants caused by Pythium species. Pythium species used in this study were P. vipa (isolate 09), P. dissotocum (isolate 41-08...

First report of alfalfa (Medicago sativa L.) seed rot, seedling root rot, and damping off caused by Pythium spp. in Sudanese soil

USDA-ARS?s Scientific Manuscript database

Alfalfa is an important forage crop in Sudan but has relatively low biomass yields. In September 2016 soil samples were collected from three commercial alfalfa production fields near Khartoum, Sudan with poor seedling establishment and rapid stand decline. Soil samples from each field were evaluated...

Seventeen years of research on genetics of resistance to Aphanomyces root rot of pea

USDA-ARS?s Scientific Manuscript database

Aphanomyces root rot, caused by the oomycete Aphanomyces euteiches, is a major soil borne disease of pea in many countries. Genetic resistance is considered to be a main way to control the disease. Since 2000, INRA has engaged a long-term research program to study genetic resistance to A. euteiches ...

Synthesis and Biological Activity of Substituted Urea and Thiourea Derivatives Containing 1,2,4-Triazole Moieties

DTIC Science & Technology

2013-03-19

vine grape production in the United States of America and Europe, while P. obscurans causes Phomopsis leaf blight and fruit rot of strawberry ... strawberry fruit rot diseases in Louisiana and Mississippi. Crop Protect. 2007, 26, 1449–1458. 25. Denny, W.A.; Cain, B.F.; Atwell, G.J.; Hansch, C

Fungicide rotation schemes for managing Phytophthora fruit rot of watermelon across Southeastern United States (NC, SC, and GA)

USDA-ARS?s Scientific Manuscript database

Phytophthora capsici has been documented as a pathogen on a wide variety of vegetable crops in the family Solanaceae, Cucurbitaceae, Fabaceae, and plants belonging to 23 other families. Phytophthora fruit rot of watermelons caused by P. capsici is particularly severe in southeastern U.S where optima...

QTL mapping of fruit rot resistance to the plant pathogen Phytophthora capsici in a recombinant inbred line Capsicum annuum population.

PubMed

Naegele, R P; Ashrafi, H; Hill, T A; Chin-Wo, S Reyes; Van Deynze, A E; Hausbeck, M K

2014-05-01

Phytophthora capsici is an important pepper (Capsicum annuum) pathogen causing fruit and root rot, and foliar blight in field and greenhouse production. Previously, an F6 recombinant inbred line population was evaluated for fruit rot susceptibility. Continuous variation among lines and partial and isolate-specific resistance were found. In this study, Phytophthora fruit rot resistance was mapped in the same F6 population between Criollo del Morelos 334 (CM334), a landrace from Mexico, and 'Early Jalapeno' using a high-density genetic map. Isolate-specific resistance was mapped independently in 63 of the lines evaluated and the two parents. Heritability of the resistance for each isolate at 3 and 5 days postinoculation (dpi) was high (h(2) = 0.63 to 0.68 and 0.74 to 0.83, respectively). Significant additive and epistatic quantitative trait loci (QTL) were identified for resistance to isolates OP97 and 13709 (3 and 5 dpi) and 12889 (3 dpi only). Mapping of fruit traits showed potential linkage with few disease resistance QTL. The partial fruit rot resistance from CM334 suggests that this may not be an ideal source for fruit rot resistance in pepper.

Endophytic Bacteria Improve Plant Growth, Symbiotic Performance of Chickpea (Cicer arietinum L.) and Induce Suppression of Root Rot Caused by Fusarium solani under Salt Stress.

PubMed

Egamberdieva, Dilfuza; Wirth, Stephan J; Shurigin, Vyacheslav V; Hashem, Abeer; Abd Allah, Elsayed F

2017-01-01

Salinity causes disturbance in symbiotic performance of plants, and increases susceptibility of plants to soil-borne pathogens. Endophytic bacteria are an essential determinant of cross-tolerance to biotic and abiotic stresses in plants. The aim of this study was to isolate non-rhizobial endophytic bacteria from the root nodules of chickpea ( Cicer arietinum L.), and to assess their ability to improve plant growth and symbiotic performance, and to control root rot in chickpea under saline soil conditions. A total of 40 bacterial isolates from internal root tissues of chickpea grown in salinated soil were isolated. Four bacterial isolates, namely Bacillus cereus NUU1 , Achromobacter xylosoxidans NUU2, Bacillus thuringiensis NUU3, and Bacillus subtilis NUU4 colonizing root tissue demonstrated plant beneficial traits and/or antagonistic activity against F. solani and thus were characterized in more detail. The strain B. subtilis NUU4 proved significant plant growth promotion capabilities, improved symbiotic performance of host plant with rhizobia, and promoted yield under saline soil as compared to untreated control plants under field conditions. A combined inoculation of chickpea with M. ciceri IC53 and B. subtilis NUU4 decreased H 2 O 2 concentrations and increased proline contents compared to the un-inoculated plants indicating an alleviation of adverse effects of salt stress. Furthermore, the bacterial isolate was capable to reduce the infection rate of root rot in chickpea caused by F. solani . This is the first report of F. solani causing root rot of chickpea in a salinated soil of Uzbekistan. Our findings demonstrated that the endophytic B. subtilis strain NUU4 provides high potentials as a stimulator for plant growth and as biological control agent of chickpea root rot under saline soil conditions. These multiple relationships could provide promising practical approaches to increase the productivity of legumes under salt stress.

Endophytic Bacteria Improve Plant Growth, Symbiotic Performance of Chickpea (Cicer arietinum L.) and Induce Suppression of Root Rot Caused by Fusarium solani under Salt Stress

PubMed Central

Egamberdieva, Dilfuza; Wirth, Stephan J.; Shurigin, Vyacheslav V.; Hashem, Abeer; Abd_Allah, Elsayed F.

2017-01-01

Salinity causes disturbance in symbiotic performance of plants, and increases susceptibility of plants to soil-borne pathogens. Endophytic bacteria are an essential determinant of cross-tolerance to biotic and abiotic stresses in plants. The aim of this study was to isolate non–rhizobial endophytic bacteria from the root nodules of chickpea (Cicer arietinum L.), and to assess their ability to improve plant growth and symbiotic performance, and to control root rot in chickpea under saline soil conditions. A total of 40 bacterial isolates from internal root tissues of chickpea grown in salinated soil were isolated. Four bacterial isolates, namely Bacillus cereus NUU1, Achromobacter xylosoxidans NUU2, Bacillus thuringiensis NUU3, and Bacillus subtilis NUU4 colonizing root tissue demonstrated plant beneficial traits and/or antagonistic activity against F. solani and thus were characterized in more detail. The strain B. subtilis NUU4 proved significant plant growth promotion capabilities, improved symbiotic performance of host plant with rhizobia, and promoted yield under saline soil as compared to untreated control plants under field conditions. A combined inoculation of chickpea with M. ciceri IC53 and B. subtilis NUU4 decreased H2O2 concentrations and increased proline contents compared to the un-inoculated plants indicating an alleviation of adverse effects of salt stress. Furthermore, the bacterial isolate was capable to reduce the infection rate of root rot in chickpea caused by F. solani. This is the first report of F. solani causing root rot of chickpea in a salinated soil of Uzbekistan. Our findings demonstrated that the endophytic B. subtilis strain NUU4 provides high potentials as a stimulator for plant growth and as biological control agent of chickpea root rot under saline soil conditions. These multiple relationships could provide promising practical approaches to increase the productivity of legumes under salt stress. PMID:29033922

GmPGIP3 enhanced resistance to both take-all and common root rot diseases in transgenic wheat.

PubMed

Wang, Aiyun; Wei, Xuening; Rong, Wei; Dang, Liang; Du, Li-Pu; Qi, Lin; Xu, Hui-Jun; Shao, Yanjun; Zhang, Zengyan

2015-05-01

Take-all (caused by the fungal pathogen Gaeumannomyces graminis var. tritici, Ggt) and common root rot (caused by Bipolaris sorokiniana) are devastating root diseases of wheat (Triticum aestivum L.). Development of resistant wheat cultivars has been a challenge since no resistant wheat accession is available. GmPGIP3, one member of polygalacturonase-inhibiting protein (PGIP) family in soybean (Glycine max), exhibited inhibition activity against fungal endopolygalacturonases (PGs) in vitro. In this study, the GmPGIP3 transgenic wheat plants were generated and used to assess the effectiveness of GmPGIP3 in protecting wheat from the infection of Ggt and B. sorokiniana. Four independent transgenic lines were identified by genomic PCR, Southern blot, and reverse transcription PCR (RT-PCR). The introduced GmPGIP3 was integrated into the genomes of these transgenic lines and could be expressed. The expressing GmPGIP3 protein in these transgenic wheat lines could inhibit the PGs produced by Ggt and B. sorokiniana. The disease response assessments postinoculation showed that the GmPGIP3-expressing transgenic wheat lines displayed significantly enhanced resistance to both take-all and common root rot diseases caused by the infection of Ggt and B. sorokiniana. These data suggested that GmPGIP3 is an attractive gene resource in improving resistance to both take-all and common root rot diseases in wheat.

Effects of pex1 disruption on wood lignin biodegradation, fruiting development and the utilization of carbon sources in the white-rot Agaricomycete Pleurotus ostreatus and non-wood decaying Coprinopsis cinerea.

PubMed

Nakazawa, Takehito; Izuno, Ayako; Horii, Masato; Kodera, Rina; Nishimura, Hiroshi; Hirayama, Yuichiro; Tsunematsu, Yuta; Miyazaki, Yasumasa; Awano, Tatsuya; Muraguchi, Hajime; Watanabe, Kenji; Sakamoto, Masahiro; Takabe, Keiji; Watanabe, Takashi; Isagi, Yuji; Honda, Yoichi

2017-12-01

Peroxisomes are well-known organelles that are present in most eukaryotic organisms. Mutant phenotypes caused by the malfunction of peroxisomes have been shown in many fungi. However, these have never been investigated in Agaricomycetes, which include white-rot fungi that degrade wood lignin in nature almost exclusively and play an important role in the global carbon cycle. Based on the results of a forward genetics study to identify mutations causing defects in the ligninolytic activity of the white-rot Agaricomycete Pleurotus ostreatus, we report phenotypes of pex1 disruptants in P. ostreatus, which are defective in two major features of white-rot Agaricomycetes: lignin biodegradation and mushroom formation. Pex1 disruption was also shown to cause defects in the hyphal growth of P. ostreatus on certain sawdust and minimum media. We also demonstrated that pex1 is essential for fruiting initiation in the non-wood decaying Agaricomycete Coprinopsis cinerea. However, unlike P. ostreatus, significant defects in hyphal growth on the aforementioned agar medium were not observed in C. cinerea. This result, together with previous C. cinerea genetic studies, suggests that the regulation mechanisms for the utilization of carbon sources are altered during the evolution of Agaricomycetes or Agaricales. Copyright © 2017 Elsevier Inc. All rights reserved.

21 CFR 522.2640 - Tylosin.

Code of Federal Regulations, 2011 CFR

2011-04-01

..., pneumonia) usually associated with Pasteurella multocida and Arcanobacterium pyogenes; foot rot (necrotic... caused by Mycoplasma hyosynoviae; swine pneumonia caused by Pasteurella spp.; swine erysipelas caused by..., tracheitis, laryngitis, tonsillitis, and pneumonia caused by Staphylococci spp., hemolytic Streptococci spp...

21 CFR 522.2640 - Tylosin.

Code of Federal Regulations, 2012 CFR

2012-04-01

..., pneumonia) usually associated with Pasteurella multocida and Arcanobacterium pyogenes; foot rot (necrotic... caused by Mycoplasma hyosynoviae; swine pneumonia caused by Pasteurella spp.; swine erysipelas caused by..., tracheitis, laryngitis, tonsillitis, and pneumonia caused by Staphylococci spp., hemolytic Streptococci spp...

21 CFR 522.2640 - Tylosin.

Code of Federal Regulations, 2010 CFR

2010-04-01

..., pneumonia) usually associated with Pasteurella multocida and Arcanobacterium pyogenes; foot rot (necrotic... caused by Mycoplasma hyosynoviae; swine pneumonia caused by Pasteurella spp.; swine erysipelas caused by..., tracheitis, laryngitis, tonsillitis, and pneumonia caused by Staphylococci spp., hemolytic Streptococci spp...

21 CFR 522.2640 - Tylosin.

Code of Federal Regulations, 2013 CFR

2013-04-01

..., pneumonia) usually associated with Pasteurella multocida and Arcanobacterium pyogenes; foot rot (necrotic... caused by Mycoplasma hyosynoviae; swine pneumonia caused by Pasteurella spp.; swine erysipelas caused by..., tracheitis, laryngitis, tonsillitis, and pneumonia caused by Staphylococci spp., hemolytic Streptococci spp...

Genetics and Molecular Mapping of Black Rot Resistance Locus Xca1bc on Chromosome B-7 in Ethiopian Mustard (Brassica carinata A. Braun)

PubMed Central

Sharma, Brij Bihari; Kalia, Pritam; Yadava, Devendra Kumar; Singh, Dinesh; Sharma, Tilak Raj

2016-01-01

Black rot caused by Xanthomonas campestris pv. campestris (Pam.) Dowson is the most destructive disease of cauliflower causing huge loss to the farmers throughout the world. Since there are limited sources of resistance to black rot in B. oleracea (C genome Brassica), exploration of A and B genomes of Brassica was planned as these were thought to be potential reservoirs of black rot resistance gene(s). In our search for new gene(s) for black rot resistance, F2 mapping population was developed in Brassica carinata (BBCC) by crossing NPC-17, a susceptible genotype with NPC-9, a resistant genotype. Out of 364 Intron length polymorphic markers and microsatellite primers used in this study, 41 distinguished the parental lines. However, resistant and susceptible bulks could be distinguished by three markers At1g70610, SSR Na14-G02 and At1g71865 which were used for genotyping of F2 mapping population. These markers were placed along the resistance gene, according to order, covering a distance of 36.30 cM. Intron length polymorphic markers At1g70610 and At1g71865 were found to be linked to black rot resistance locus (Xca1bc) at 6.2 and 12.8 cM distance, respectively. This is the first report of identification of markers linked to Xca1bc locus in Brassica carinata on B-7 linkage group. Intron length polymorphic markers provided a novel and attractive option for marker assisted selection due to high cross transferability and cost effectiveness for marker assisted alien gene introgression into cauliflower. PMID:27023128

Possible sources of genetic resistance in oil palm (Elaeis guineensis Jacq.) to basal stem rot caused by Ganoderma boninense--prospects for future breeding.

PubMed

Durand-Gasselin, T; Asmady, H; Flori, A; Jacquemard, J C; Hayun, Z; Breton, F; de Franqueville, H

2005-01-01

Oil palm estates in southeast Asia suffer from substantial losses due to basal stem rot caused by Ganoderma boninense. Field observations have been carried out in North Sumatra, Indonesia, on a series of planting materials of known origin. Differences in susceptibility to the disease have been detected within the two Elaeis species, guineensis and oleifera. Within Elaeis guineensis, material of Deli origin is highly susceptible compared to material of African origin. It is also possible to detect differences in reaction between parents and between crosses within a given origin. The variability of resistance to basal stem rot within the same cross is also illustrated by the diverse responses of clones derived from palms of the same origin. The prospects opened up by these results are discussed, and the importance of performing an early selection test is highlighted.

Biodiversity of complexes of mycotoxigenic fungal species associated with Fusarium ear rot of maize and Aspergillus rot of grape.

PubMed

Logrieco, A; Moretti, A; Perrone, G; Mulè, G

2007-10-20

Fusarium ear rot of maize and Aspergillus rot of grape are two examples of important plant diseases caused by complexes of species of mycotoxigenic fungi. These complexes of species tend to be closely related, produce different classes of mycotoxins, and can induce disease under different environmental conditions. The infection of maize and grape with multiple fungal species and the resulting production of large classes of mycotoxins is an example of mutual aggressiveness of microorganisms toward host species as well as to humans and animals that eat feed or food derived from the infected and contaminated plants. Infection of crop plant with a complex of microbial species certainly represents a greater threat to a crop plant and to human and animal health than infection of the plant with a single fungal species.

First report of Lasmenia sp. causing rachis necrosis, flower abortion, fruit rot and leaf spots on rambutan in Puerto Rico

USDA-ARS?s Scientific Manuscript database

Rambutan is an exotic tropical fruit that has increased in commercial importance for growers in Puerto Rico. In 2008 and 2009, fruit rot and lesions on both leaves and inflorescences were observed. A total of 276 diseased samples from these plant parts were collected at commercial orchards, Agricult...

Laminated root rot damage in a young Douglas-fir stand.

Treesearch

E.E. Nelson

1980-01-01

Damage occurring from the disease laminated root rot {Phellinus weirii (Murr.) Gilbertson) on two 10-acre plots in a young (40-year-old) stand of Douglas-fir was studied for 25 years. After 25 years, nearly 5 percent of the basal area was killed by the disease. Stand damage caused by vegetative spread of the fungus was significantly related to...

Association of Enterobacter cloacae and other bacteria with onion bulb rot in the Columbia Basin of Washington and Oregon, USA

USDA-ARS?s Scientific Manuscript database

Approximately 1.6 million metric tons of onion bulbs are produced annually in the Pacific Northwest USA. Bulb decay can be a major problem and is caused by a variety of plant pathogens. Onion bulbs exhibiting symptoms of bacterial rot were sampled to determine the causal agents. Enterobacter cloacae...

Genotyping-by-sequencing uncovers the introgression alien segments associated with Sclerotinia basal stalk rot resistance from wild species—I. Helianthus argophyllus and H. petiolaris

USDA-ARS?s Scientific Manuscript database

Basal stalk rot (BSR), caused by Sclerotinia Sclerotiorum, is a devastating disease in sunflower worldwide. The progress of breeding for Sclerotinia BSR resistance has been hampered due to the lack of effective sources of resistance for cultivated sunflower. Our objective was to transfer BSR resista...

Heart Rots of Red and White Firs

Treesearch

J.W. Kimmey; H.H. Jr. Bynum

1961-01-01

Heart rots, caused by fungi that attack the heartwood of living trees, are responsible for the greatest volume loss sustained by California red fir (Abies magnifica A. Murr.) and white fir (A. concolor (Gord. and Glend.) Lindl.). These two firs comprise 25 percent of the commercial timber of California. More than 13 percent of the volume in these firs is useless cull...

Differential stress-induced regulation of two quinone reductases in the brown rot Basidiomycete Gloeophyllum trabeum

Treesearch

Roni Cohen; Melissa R. Suzuki; Kenneth E. Hammel

2004-01-01

Quinone reductases (QRDs) have two important functions in the basidiomycete Gloeophyllum trabeum, which causes brown rot of wood. First, a QRD is required to generate biodegradative hydroxyl radicals via redox cycling between two G. trabeum extracellular metabolites, 2,5-dimethoxyhydroquinone (2,5-DMHQ) and 2,5-dimethoxy-1,4-benzoquinone (2,5- DMBQ). Second, because 2,...

Short-Read Sequencing for Genomic Analysis of the Brown Rot Fungus Fibroporia radiculosa

Treesearch

J. D. Tang; A. D. Perkins; T. S. Sonstegard; S. G. Schroeder; S. C. Burgess; S. V. Diehl

2012-01-01

The feasibility of short-read sequencing for genomic analysis was demonstrated for Fibroporia radiculosa, a copper-tolerant fungus that causes brown rot decay of wood. The effect of read quality on genomic assembly was assessed by filtering Illumina GAIIx reads from a single run of a paired-end library (75-nucleotide read length and 300-bp fragment...

Occurrence of the root-rot pathogen, Fusarium commune, in midwestern and western United States

Treesearch

J. E. Stewart; R. K. Dumroese; N. B. Klopfenstein; M. -S. Kim

2012-01-01

Fusarium commune can cause damping-off and root rot of conifer seedlings in forest nurseries. The pathogen is only reported in Oregon, Idaho, and Washington within United States. Fusarium isolates were collected from midwestern and western United States to determine occurrence of this pathogen. DNA sequences of mitochondrial small subunit gene were used to identify F....

Long-term effects of stump removal to control root rot on forest soil bulk density, soil carbon and nitrogen content.

Treesearch

D. Zabowski; D. Chambrear; N. Rotramel; W.G. Thies

2008-01-01

Phellinus weirii (Mum.) Gilb is a native pathogen in the forests of the Northwestern United States causing laminated root rot and mortality in Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) and other susceptible conifer species. This facultative saprophyte is a natural part of the ecosystem, present in most Douglas-fir...

Multiplex assay for the quantitative assessment of Rhizoctonia solani AG2-2, AG4 and Rhizoctonia zeae from the soil

USDA-ARS?s Scientific Manuscript database

Rhizoctonia solani causes damping off and root and crown rot in sugar beets resulting in substantial losses in the field and during storage. Root rot is a difficult fungal disease to diagnose and manage, as the pathogen is usually not detected until after damage has occurred. The objective of this s...

Pectobacterium carotovorum. subsp. brasiliense is a causal agent of bacterial leaf rot of tobacco in China

USDA-ARS?s Scientific Manuscript database

A new leaf rot disease of tobacco was found in fields of the Shaowu region, Fujian Province of China in 2015. A typical symptom was necrosis along the main or lateral veins of tobacco leaves, eventually causing wilting and death of the leaves, while the necrosis spread no further than the epidermis ...

Natural decomposition of hornbeam wood decayed by the white rot fungus Trametes versicolor.

PubMed

Karim, Maryam; Daryaei, Mehrdad Ghodskhah; Torkaman, Javad; Oladi, Reza; Ghanbary, Mohammad Ali Tajick; Bari, Ehsan; Yilgor, Nural

2017-01-01

The impacts of white-rot fungi on altering wood chemistry have been studied mostly in vitro. However, in vivo approaches may enable better assessment of the nature of interactions between saprotrophic fungi and host tree in nature. Hence, decayed and sound wood samples were collected from a naturally infected tree (Carpinus betulus L.). Fruiting bodies of the white rot fungus Trametes versicolor grown on the same tree were identified using rDNA ITS sequencing. Chemical compositions (cellulose and lignin) of both sound and infected wood were studied. FT-IR spectroscopy was used to collect spectra of decayed and un-decayed wood samples. The results of chemical compositions indicated that T. versicolor reduced cellulose and lignin in similar quantities. Fungal activities in decayed wood causes serious decline in pH content. The amount of alcohol-benzene soluble extractives was severely decreased, while a remarkable increase was found in 1% sodium hydroxide soluble and hot water extractive contents in the decayed wood samples, respectively. FT-IR analyses demonstrated that T. versicolor causes simultaneous white rot in the hornbeam tree in vivo which is in line with in vitro experiments.

Recent Developments in Using Advanced Sequencing Technologies for the Genomic Studies of Lignin and Cellulose Degrading Microorganisms

PubMed Central

Kameshwar, Ayyappa kumar Sista; Qin, Wensheng

2016-01-01

Lignin is a complex polyphenyl aromatic compound which exists in tight associations with cellulose and hemicellulose to form plant primary and secondary cell wall. Lignocellulose is an abundant renewable biomaterial present on the earth. It has gained much attention in the scientific community in recent years because of its potential applications in bio-based industries. Microbial degradation of lignocellulose polymers was well studied in wood decaying fungi. Based on the plant materials they degrade these fungi were classified as white rot, brown rot and soft rot. However, some groups of bacteria belonging to the actinomycetes, α-proteobacteria and β-proteobacteria were also found to be efficient in degrading lignocellulosic biomass but not well understood unlike the fungi. In this review we focus on recent advancements deployed for finding and understanding the lignocellulose degradation by microorganisms. Conventional molecular methods like sequencing 16s rRNA and Inter Transcribed Spacer (ITS) regions were used for identification and classification of microbes. Recent progression in genomics mainly next generation sequencing technologies made the whole genome sequencing of microbes possible in a great ease. The whole genome sequence studies reveals high quality information about genes and canonical pathways involved in the lignin and other cell wall components degradation. PMID:26884714

Black pod: diverse pathogens with a global impact on cocoa yield.

PubMed

Guest, David

2007-12-01

ABSTRACT Pathogens of the Straminipile genus Phytophthora cause significant disease losses to global cocoa production. P. megakarya causes significant pod rot and losses due to canker in West Africa, whereas P. capsici and P. citrophthora cause pod rots in Central and South America. The global and highly damaging P. palmivora attacks all parts of the cocoa tree at all stages of the growing cycle. This pathogen causes 20 to 30% pod losses through black pod rot, and kills up to 10% of trees annually through stem cankers. P. palmivora has a complex disease cycle involving several sources of primary inoculum and several modes of dissemination of secondary inoculum. This results in explosive epidemics during favorable environmental conditions. The spread of regional pathogens must be prevented by effective quarantine barriers. Resistance to all these Phytophthora species is typically low in commercial cocoa genotypes. Disease losses can be reduced through integrated management practices that include pruning and shade management, leaf mulching, regular and complete harvesting, sanitation and pod case disposal, appropriate fertilizer application and targeted fungicide use. Packaging these options to improve uptake by smallholders presents a major challenge for the industry.

The Induction of Noble Rot (Botrytis cinerea) Infection during Postharvest Withering Changes the Metabolome of Grapevine Berries (Vitis vinifera L., cv. Garganega)

PubMed Central

Negri, Stefano; Lovato, Arianna; Boscaini, Filippo; Salvetti, Elisa; Torriani, Sandra; Commisso, Mauro; Danzi, Roberta; Ugliano, Maurizio; Polverari, Annalisa; Tornielli, Giovanni B.; Guzzo, Flavia

2017-01-01

The natural or induced development of noble rot caused by the fungus Botrytis cinerea during the late stages of grapevine (Vitis vinifera L.) berry ripening is used in some traditional viticulture areas to produce high-quality wines such as Sauternes and Tokaji. In this research, we wanted to verify if by changing the environmental conditions during post-harvest withering we could induce the noble rot development on harvested berries in order to positively change the wine produced from withered Garganega berries. Therefore, we exposed the berries to postharvest withering under normal or artificially humid conditions, the latter to induce noble rot. The presence of noble rot symptoms was associated with the development of B. cinerea in the berries maintained under humid conditions. The composition of infected and non-infected berries was investigated by untargeted metabolomics using liquid chromatography/mass spectrometry. We also explored the effects of the two withering methods on the abundance of volatile organic compounds in wine by yeast-inoculated micro-fermentation followed by targeted gas chromatography/mass spectrometry. These experiments revealed significant metabolic differences between berries withered under normal and humid conditions, indicating that noble rot affects berry metabolism and composition. As well as well-known botrytization markers, we detected two novel lipids that have not been observed before in berries infected with noble rot. Unraveling the specific metabolic profile of berries infected with noble rot may help to determine the compounds responsible for the organoleptic quality traits of botrytized Garganega wines. PMID:28680428

Application of chloropicrin to Douglas-fir stumps to control laminated root rot does not affect infection or growth of regeneration 16 growing seasons after treatment.

Treesearch

Walter G. Thies; Douglas J. Westlind

2006-01-01

Phellinus weirii (Murr.) Gilb. causes laminated root rot (LRR), a major disease affecting growth and survival of Pseudotsuga menziesii (Mirb.) Franco (Douglas-fir) and other commercially important conifer species throughout the Pacific Northwest. This disease is known to spread to a replacement stand by root contact between...

Occurrence of the root-rot pathogen, Fusarium commune, in forest nurseries of the midwestern and western United States

Treesearch

Mee-Sook Kim; Jane E. Stewart; R. Kasten Dumroese; Ned B. Klopfenstein

2012-01-01

Fusarium commune can cause damping-off and root rot of conifer seedlings in forest nurseries, and this pathogen has been previously reported from Oregon, Idaho, and Washington, USA. We collected Fusarium isolates from additional nurseries in the midwestern and western USA to more fully determine occurrence of this pathogen. We used DNA sequences of the mitochondrial...

Relation of heart rots to mortality of red spruce in the Green Mountain National Forest

Treesearch

Paul V. Mook; Harold G. Eno

1956-01-01

Several years ago, old-growth red spruce at high elevations in the Green Mountain National Forest were observed to be dying. Entomologists and pathologists who examined the affected area found no insect or fungus that was obviously causing the deaths. However, many of the dead and dying trees were butt-rotted by the fungus Polyporus borealis. Though it seemed unlikely...

Fungal hydroquinones contribute to brown rot of wood

Treesearch

Melissa R. Suzuki; Christopher G. Hunt; Carl J. Houtman; Zachary D. Dalebroux; Kenneth E. Hammel

2006-01-01

The fungi that cause brown rot of wood initiate lignocellulose breakdown with an extracellular Fenton system in which Fe2+ and H2O2 react to produce hydroxyl radicals (•OH), which then oxidize and cleave the wood holocellulose. One such fungus, Gloeophyllum trabeum, drives Fenton chemistry on defined media by reducing Fe3+ and O2 with two extracellular hydroquinones,...

Spatial mapping of extracellular oxidant production by a white rot basidiomycete on wood reveals details of ligninolytic mechanism

Treesearch

Christopher G. Hunt; Carl J. Houtman; Don C. Jones; Peter Kitin; Premsagar Korripally; Kenneth E. Hammel

2013-01-01

Oxidative cleavage of the recalcitrant plant polymer lignin is a crucial step in global carbon cycling, and is accomplished most efficiently by fungi that cause white rot of wood. These basidiomycetes secrete many enzymes and metabolites with proposed ligninolytic roles, and it is not clear whether all of these agents are physiologically important during attack on...

Accelerated detection of brown-rot decay : comparison of soil block test, chemical analysis, mechanical properties, and immunodetection

Treesearch

C. A. Clausen; S. N. Kartal

2003-01-01

Early detection of wood decay is critical because decay fungi can cause rapid structural failure. The objective of this study was to compare the sensitivity of different methods purported to detect brown-rot decay in the early stages of development. The immunodiagnostic wood decay (IWD)test, soil block test/cake pan test, mechanical property tests, and chemical...

A novel, multiplexed, probe-based quantitative PCR assay for the soybean root- and stem-rot pathogen, Phytophthora sojae, utilizes its transposable element

USDA-ARS?s Scientific Manuscript database

Phytophthora root rot of soybean (Glycine max Merr.) is caused by the oomycete Phytophthora sojae (Kaufm. and Gerd.). P. sojae has a narrow host range, consisting primarily of soybean, and it is a serious pathogen worldwide. It exists in root and stem tissues as mycelium, wherein it can form oospo...

Genome and secretome analysis of the hemibiotrophic fungal pathogen, Moniliophthora roreri, which causes frosty pod rot disease of cacao: mechanisms of the biotrophic and necrotrophic phases

USDA-ARS?s Scientific Manuscript database

Background: Moniliophthora roreri is the causal agent of Frosty pod rot (FPR) disease of Theobroma cacao, the source of chocolate and is one of the most destructive diseases of cacao in the Americas. This Basidiomycete only infects cacao pods and has an extended biotrophic phase lasting up to sixty ...

Phytophthora megakarya and P. palmivora, closely related causal agents of cacao black pod rot, underwent increases in genome sizes and gene numbers by different mechanisms

USDA-ARS?s Scientific Manuscript database

Phytophthora megakarya (Pmeg) and P. palmivora (Ppal) are closely related species causing black pod rot of cacao. While Ppal is a cosmopolitan plant pathogen, cacao is the only known host of importance for Pmeg. Pmeg is more virulent on cacao than Ppal. Therefore, we have sequenced both the Pmeg and...

Common wood decay fungi found in the Caribbean Basin

Treesearch

D. Jean Lodge

2016-01-01

There are hundreds of wood-decay fungi in the Caribbean Basin, but relatively few of these are likely to grow on manmade structures built of wood or wood-composites. The wood-decay fungi of greatest concern are those that cause brown-rot, and especially brown-rot fungi that are resistant to copper-based wood preservatives. Some fungi that grow in the Caribbean and...

SEM study of the effects of bacteria and yeasts on wood decay by brown and white-rot fungi. [Enterobacter, Cryptococcus Pichia, and Saccharomyces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blanchette, R.A.; Shaw, C.G.; Cohen, A.L.

The scanning electron microscope was used to 1) examine the associations among microorganisms during wood decay and 2) observe the effect of these organisms on degradation of cell wall components. Bacteria (Enterobacter) and yeasts (Cryptococcus Pichia, and Saccharomyces) were found to have a mutualistic association with a white-rot fungus during decay of coniferous wood. Coriolus (Polyporus versicolar) degraded cell wall components in a typical ''erosion trough'' manner (i.e., by lysing zones around fungal hyphae). Bacteria and yeasts were seen only in these lysed zones. Typical gross decay patterns caused by the white-rot fungus were unaltered by bacteria and yeasts. Themore » SEM study suggests that the decay process is enhanced when these organisms are associated. In contrast, the same bacteria and yeasts were inhibitory when combined with a brown-rot fungus.« less

When Genome-Based Approach Meets the “Old but Good”: Revealing Genes Involved in the Antibacterial Activity of Pseudomonas sp. P482 against Soft Rot Pathogens

PubMed Central

Krzyżanowska, Dorota M.; Ossowicki, Adam; Rajewska, Magdalena; Maciąg, Tomasz; Jabłońska, Magdalena; Obuchowski, Michał; Heeb, Stephan; Jafra, Sylwia

2016-01-01

Dickeya solani and Pectobacterium carotovorum subsp. brasiliense are recently established species of bacterial plant pathogens causing black leg and soft rot of many vegetables and ornamental plants. Pseudomonas sp. strain P482 inhibits the growth of these pathogens, a desired trait considering the limited measures to combat these diseases. In this study, we determined the genetic background of the antibacterial activity of P482, and established the phylogenetic position of this strain. Pseudomonas sp. P482 was classified as Pseudomonas donghuensis. Genome mining revealed that the P482 genome does not contain genes determining the synthesis of known antimicrobials. However, the ClusterFinder algorithm, designed to detect atypical or novel classes of secondary metabolite gene clusters, predicted 18 such clusters in the genome. Screening of a Tn5 mutant library yielded an antimicrobial negative transposon mutant. The transposon insertion was located in a gene encoding an HpcH/HpaI aldolase/citrate lyase family protein. This gene is located in a hypothetical cluster predicted by the ClusterFinder, together with the downstream homologs of four nfs genes, that confer production of a non-fluorescent siderophore by P. donghuensis HYST. Site-directed inactivation of the HpcH/HpaI aldolase gene, the adjacent short chain dehydrogenase gene, as well as a homolog of an essential nfs cluster gene, all abolished the antimicrobial activity of the P482, suggesting their involvement in a common biosynthesis pathway. However, none of the mutants showed a decreased siderophore yield, neither was the antimicrobial activity of the wild type P482 compromised by high iron bioavailability. A genomic region comprising the nfs cluster and three upstream genes is involved in the antibacterial activity of P. donghuensis P482 against D. solani and P. carotovorum subsp. brasiliense. The genes studied are unique to the two known P. donghuensis strains. This study illustrates that mining of microbial genomes is a powerful approach for predictingthe presence of novel secondary-metabolite encoding genes especially when coupled with transposon mutagenesis. PMID:27303376

Protective role of apigenin on rotenone induced rat model of Parkinson's disease: Suppression of neuroinflammation and oxidative stress mediated apoptosis.

PubMed

Anusha, Chandran; Sumathi, Thangarajan; Joseph, Leena Dennis

2017-05-01

Parkinson's disease (PD) is a neurodegenerative disorder characterized by the loss of dopaminergic neurons in the substantia nigra which is associated with oxidative stress, neuroinflammation and apoptosis. Apigenin (AGN), a non-mutagenic flavone found in fruits and vegetables, exhibits a variety of biological effects including anti-apoptotic, anti-inflammatory, and free radical scavenging activities. The current study was aimed to investigate the neuroprotective effects and molecular mechanisms of AGN in a rat model of PD induced by rotenone (ROT). Unilateral stereotaxic intranigral infusion of ROT caused the loss of tyrosine hydroxylase (TH) immunoreactivity in striatum and substantia nigra. AGN treatment (10 and 20 mg/kg, i.p.) showed a significant improvement in behavioral, biochemical and mitochondrial enzyme activities as compared to ROT exposed rats. The mRNA expression of inflammatory markers and neurotrophic factors was quantified by reverse transcriptase polymerase chain reaction (RT-PCR). Administration of AGN significantly attenuated the upregulation of NF-κB gene expression in ROT induced group and prevented the neuroinflammation in substantia nigra pars compacta (SNpc). Further, AGN inhibited the release of pro-inflammatory cytokines TNF- α, IL-6 and pro-inflammatory enzyme iNOS-1 induced by ROT. Additionally, AGN prevents the reduction of neurotrophic factors BDNF and GDNF mRNA expression in ROT lesioned rats. Immunoblot results illustrated that AGN treatment downregulated α-synuclein aggregation and upregulated the TH protein expression as well as dopamine D2 receptor (D2R) expression in ROT lesioned rats. Thus, the present findings collectively suggest that AGN exerts its neuroprotection in ROT model of PD and may act as an effective agent for treatment of PD. Copyright © 2017 Elsevier B.V. All rights reserved.

Population genomic analyses of the brown root-rot pathogen, Phellinus noxius, examine potential invasive spread among Pacific islands

Treesearch

Jane E. Stewart; Mee-Sook Kim; Louise Shuey; Norio Sahashi; Yuko Ota; Robert L. Schlub; Phil G. Cannon; Ned B. Klopfenstein

2016-01-01

Phellinus noxius (Corner) G. H. Cunn is a vastly destructive, fast-growing fungal pathogen that affects a wide range of woody hosts in pan-tropical areas, including Asia, Australia, Africa, and Oceania (Ann et al. 2002; Figure 1) . This pathogen causes brown root-rot disease on cacao, coffee, and rubber, as well as diverse fruit, nut, ornamental, and other...

Relative in vitro wood decay resistance of sapwood from landscape trees of southern temperate regions

Treesearch

Manuela Baietto; A. Dan Wilson

2010-01-01

The development of wood decay caused by 12 major root-rot and trunk-rot fungi was investigated in vitro with sapwood extracted from nine ornamental and landscape hardwood and conifer species native to southern temperate regions of North America, Europe, and the lower Mississippi Delta. Wood decay rates based on dry weight loss for 108 host tree–wood decay fungi...

Biological Degradation of Chinese Fir with Trametes Versicolor (L.) Lloyd

PubMed Central

Chen, Meiling; Wang, Chuangui; Fei, Benhua; Ma, Xinxin; Zhang, Bo; Zhang, Shuangyan; Huang, Anmin

2017-01-01

Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) has been an important afforestation species in northeast China. It has obvious defects of buckling and cracking easily, which are caused by its chemical components. Trametes versicolor (L.) Lloyd, a white-rot fungus, can decompose the cellulose, hemicellulose, and lignin in the wood. White-rot fungus was used to biologically degrade Chinese fir wood. The effects of different degradation time on the Chinese fir wood’s mechanical properties, micromorphology, chemical components, and crystallinity were studied. The results showed that the heartwood of Chinese fir was more durable than the sapwood and the durability class of Chinese fir was III. Trametes versicolor (L.) Lloyd had a greater influence on the mechanical properties (especially with respect to the modulus of elasticity (MOE)) for the sapwood. Trametes versicolor (L.) Lloyd degraded Chinese fir and colonized the lumen of various wood cell types in Chinese fir, penetrated cell walls via pits, caused erosion troughs and bore holes, and removed all cell layers. The ability of white-rot fungus to change the chemical composition mass fraction for Chinese fir was: hemicellulose > lignin > cellulose. The durability of the chemical compositions was: lignin > cellulose > hemicellulose. The crystallinity of the cellulose decreased and the mean size of the ordered (crystalline) domains increased after being treated by white-rot fungus. PMID:28773191

Isolation, characterization, and formulation of antagonistic bacteria for the management of seedlings damping-off and root rot disease of cucumber.

PubMed

Khabbaz, Salah Eddin; Abbasi, Pervaiz A

2014-01-01

Antagonistic bacteria are common soil inhabitants with potential to be developed into biofungicides for the management of seedling damping-off, root rot, and other soil-borne diseases of various crops. In this study, antagonistic bacteria were isolated from a commercial potato field and screened for their growth inhibition of fungal and oomycete pathogens in laboratory tests. The biocontrol potential of the 3 most effective antagonistic bacteria from the in vitro tests was evaluated against seedling damping-off and root rot of cucumber caused by Pythium ultimum. Based on phenotypic characteristics, biochemical tests, and sequence analysis of 16S-23S rDNA gene, the 3 antagonistic bacteria were identified as Pseudomonas fluorescens (isolate 9A-14), Pseudomonas sp. (isolate 8D-45), and Bacillus subtilis (isolate 8B-1). All 3 bacteria promoted plant growth and suppressed Pythium damping-off and root rot of cucumber seedlings in growth-room assays. Both pre- and post-planting application of these bacteria to an infested peat mix significantly increased plant fresh masses by 113%-184% and percentage of healthy seedlings by 100%-290%, and decreased damping-off and root rot severity by 27%-50%. The peat and talc formulations of these antagonistic bacteria applied as seed or amendment treatments to the infested peat mix effectively controlled Pythium damping-off and root rot of cucumber seedlings and enhanced plant growth. The survival of all 3 antagonistic bacteria in peat and talc formulations decreased over time at room temperature, but the populations remained above 10(8) CFU/g during the 180-day storage period. The peat formulation of a mixture of 3 bacteria was the best seed treatment, significantly increasing the plant fresh masses by 245% as compared with the Pythium control, and by 61.4% as compared with the noninfested control. This study suggests that the indigenous bacteria from agricultural soils can be developed and formulated as biofungicides for minimizing the early crop losses caused by seedling damping-off and root rot diseases.

Deception Island, Antarctica, harbors a diverse assemblage of wood decay fungi.

PubMed

Held, Benjamin W; Blanchette, Robert A

2017-02-01

Very little is known about fungal diversity in Antarctica as compared to other biomes and how these important organisms function in this unusual ecosystem. Perhaps one of the most unusual ecosystems is that of Deception Island; an active volcanic island part of the South Shetland Islands of the Antarctic Peninsula. Here we describe the fungal diversity associated with historic wood from structures on the island, which reveals a diverse fungal assemblage of known wood decay fungi as well as the discovery of undescribed species. The major group of wood decay fungi identified were species of Cadophora and as shown in previous studies in other geographic regions of Antarctica, they caused a soft-rot type of decay in the introduced woods. Additionally, unlike other areas of Antarctica that have been studied, filamentous basidiomycetes (Hypochniciellum spp. and Pholiota spp.) were also identified that have different modes of degradation including brown and white rot. Matches of fungal sequences to known species in temperate regions likely introduced on building materials indicates human influences and volcanic activity have greatly impacted fungal diversity. Lahars (mudslides from volcanic activity) have partially buried many of the structures and the buried environment as well as the moist, warm soils provided conditions conducive for fungal growth that are not found in other regions of Antarctica. The diverse assemblage of decay fungi and different forms of wood decomposition add to the difficulty of conserving wooden structures at these important polar heritage sites. Copyright © 2016 British Mycological Society. Published by Elsevier Ltd. All rights reserved.

Thyme and Savory Essential Oil Vapor Treatments Control Brown Rot and Improve the Storage Quality of Peaches and Nectarines, but Could Favor Gray Mold

PubMed Central

Santoro, Karin; Maghenzani, Marco; Chiabrando, Valentina; Gullino, Maria Lodovica; Giacalone, Giovanna

2018-01-01

The effect of biofumigation, through slow-release diffusors, of thyme and savory essential oils (EO), was evaluated on the control of postharvest diseases and quality of peaches and nectarines. EO fumigation was effective in controlling postharvest rots. Naturally contaminated peaches and nectarines were exposed to EO vapors for 28 days at 0 °C in sealed storage cabinets and then exposed at 20 °C for five days during shelf-life in normal atmosphere, simulating retail conditions. Under low disease pressure, most treatments significantly reduced fruit rot incidence during shelf-life, while, under high disease pressure, only vapors of thyme essential oil at the highest concentration tested (10% v/v in the diffusor) significantly reduced the rots. The application of thyme or savory EO favored a reduction of brown rot incidence, caused by Monilinia fructicola, but increased gray mold, caused by Botrytis cinerea. In vitro tests confirmed that M. fructicola was more sensitive to EO vapors than B. cinerea. Essential oil volatile components were characterized in storage cabinets during postharvest. The antifungal components of the essential oils increased during storage, but they were a low fraction of the volatile organic compounds in storage chambers. EO vapors did not influence the overall quality of the fruit, but showed a positive effect in reducing weight loss and in maintaining ascorbic acid and carotenoid content. The application of thyme and savory essential oil vapors represents a promising tool for reducing postharvest losses and preserving the quality of peaches and nectarines. PMID:29303966

Thyme and Savory Essential Oil Vapor Treatments Control Brown Rot and Improve the Storage Quality of Peaches and Nectarines, but Could Favor Gray Mold.

PubMed

Santoro, Karin; Maghenzani, Marco; Chiabrando, Valentina; Bosio, Pietro; Gullino, Maria Lodovica; Spadaro, Davide; Giacalone, Giovanna

2018-01-05

The effect of biofumigation, through slow-release diffusors, of thyme and savory essential oils (EO), was evaluated on the control of postharvest diseases and quality of peaches and nectarines. EO fumigation was effective in controlling postharvest rots. Naturally contaminated peaches and nectarines were exposed to EO vapors for 28 days at 0 °C in sealed storage cabinets and then exposed at 20 °C for five days during shelf-life in normal atmosphere, simulating retail conditions. Under low disease pressure, most treatments significantly reduced fruit rot incidence during shelf-life, while, under high disease pressure, only vapors of thyme essential oil at the highest concentration tested (10% v / v in the diffusor) significantly reduced the rots. The application of thyme or savory EO favored a reduction of brown rot incidence, caused by Monilinia fructicola , but increased gray mold, caused by Botrytis cinerea . In vitro tests confirmed that M. fructicola was more sensitive to EO vapors than B. cinerea . Essential oil volatile components were characterized in storage cabinets during postharvest. The antifungal components of the essential oils increased during storage, but they were a low fraction of the volatile organic compounds in storage chambers. EO vapors did not influence the overall quality of the fruit, but showed a positive effect in reducing weight loss and in maintaining ascorbic acid and carotenoid content. The application of thyme and savory essential oil vapors represents a promising tool for reducing postharvest losses and preserving the quality of peaches and nectarines.

Induced resistance in tomato fruit by γ-aminobutyric acid for the control of alternaria rot caused by Alternaria alternata.

PubMed

Yang, Jiali; Sun, Cui; Zhang, Yangyang; Fu, Da; Zheng, Xiaodong; Yu, Ting

2017-04-15

The study investigated the effect of γ-aminobutyric acid (GABA) on the control of alternaria rot in tomato fruit and the possible mechanism involved. Our results showed exogenous GABA could stimulate remarkable resistance to the alternaria rot, while it had no direct antifungal activity against Alternaria alternata. Moreover, the activities of antioxidant enzymes, including peroxidase, superoxide dismutase and catalase, along with the expression of these corresponding genes, were significantly induced in the GABA treatment. The obtained data suggested GABA induced resistance against the necrotrophic pathogen A. alternata, at least in part by activating antioxidant enzymes, restricting the levels of cell death caused by reactive oxygen species. Meanwhile, the key enzyme genes of GABA shunt, GABA transaminase and succinic-semialdehyde dehydrogenase, were found up-regulated in the GABA treatment. The activation of the GABA shunt might play a vital role in the resistance mechanism underpinning GABA-induced plant immunity. Copyright © 2016 Elsevier Ltd. All rights reserved.

Temporal Occurrence and Niche Preferences of Phytophthora spp. Causing Brown Rot of Citrus in the Central Valley of California.

PubMed

Hao, Wei; Miles, Timothy D; Martin, Frank N; Browne, Gregory T; Förster, Helga; Adaskaveg, James E

2018-03-01

Brown rot of citrus fruit is caused by several species of Phytophthora and is currently of serious concern for the California citrus industry. Two species, Phytophthora syringae and P. hibernalis, are quarantine pathogens in China, a major export market for California citrus. To maintain trade and estimate the risk of exporting a quarantine pathogen, the distribution and frequency of Phytophthora spp. causing brown rot of orange in major growing areas of California was investigated. Symptomatic fruit were collected from navel (winter to late spring) and Valencia (late spring to summer) orange orchards from 2013 to 2015. Species identification of isolates was based on morphological characteristics, random amplified polymorphic DNA banding patterns, and sequencing of the internal transcribed spacer and the partial cox2/spacer/cox1 regions from axenic cultures, or directly on DNA from fruit tissue using a multiplex TaqMan quantitative polymerase chain reaction assay. In winter samplings, the incidence of P. syringae based on the number of fruit with Phytophthora spp. detection ranged from 73.6 to 96.1% for the two counties surveyed. The remaining isolates were identified as P. citrophthora. In late spring or summer, only P. citrophthora was recovered. P. hibernalis and P. nicotianae were not detected in any fruit with brown rot symptoms. These results indicate that P. syringae is currently an important brown rot pathogen of citrus fruit in California during the cooler seasons of the year. In winter 2016 and 2017, P. syringae was recovered by pear baiting at a high incidence from leaf litter and from a small number of rhizosphere soil or root samples but not from living leaves on the tree. In contrast, P. citrophthora was rarely found in leaf litter but was commonly detected in the rhizosphere. Thus, leaf litter is a major inoculum source for P. syringae and this species occupies a distinct ecological niche.

Swarm Utilisation Analysis: LEO satellite observations for the ESA's SSA Space Weather network

NASA Astrophysics Data System (ADS)

Kervalishvili, Guram; Stolle, Claudia; Rauberg, Jan; Olsen, Nils; Vennerstrøm, Susanne; Gullikstad Johnsen, Magnar; Hall, Chris

2017-04-01

ESA's (European Space Agency) constellation mission Swarm was successfully launched on 22 November 2013. The three satellites achieved their final constellation on 17 April 2014 and since then Swarm-A and Swarm-C orbiting the Earth at about 470 km (flying side-by-side) and Swarm-B at about 520 km altitude. Each of Swarm satellite carries instruments with high precision to measure magnetic and electric fields, neutral and plasma densities, and TEC (Total Electron Content) for which a dual frequency GPS receiver is used. SUA (Swarm Utilisation Analysis) is a project of the ESA's SSA (Space Situational Awareness) SWE (Space Weather) program. Within this framework GFZ (German Research Centre for Geosciences, Potsdam, Germany) and DTU (National Space Institute, Kongens Lyngby, Denmark) have developed two new Swarm products ROT (Rate Of change of TEC) and PEJ (Location and intensity level of Polar Electrojets), respectively. ROT is derived as the first time derivative from the Swarm measurements of TEC at 1 Hz sampling. ROT is highly relevant for users in navigation and communications: strong plasma gradients cause GPS signal degradation or even loss of GPS signal. Also, ROT is a relevant space weather asset irrespective of geomagnetic activity, e.g., high amplitude values of ROT occur during all geomagnetic conditions. PEJ is derived from the Swarm measurements of the magnetic field strength at 1 Hz sampling. PEJ has a high-level importance for power grid companies since the polar electrojet is a major cause for ground-induced currents. ROT and PEJ together with five existing Swarm products TEC, electron density, IBI (Ionospheric Bubble Index), FAC (Field-Aligned Current), and vector magnetic field build the SUA service prototype. This prototype will be integrated into ESA's SSA Space Weather network as a federated service and will be available soon from ESA's SSA SWE Ionospheric Weather and Geomagnetic Conditions Expert Service Centres (ESCs).

Oxygen-Dependent Globin Coupled Sensor Signaling Modulates Motility and Virulence of the Plant Pathogen Pectobacterium carotovorum.

PubMed

Burns, Justin L; Jariwala, Parth B; Rivera, Shannon; Fontaine, Benjamin M; Briggs, Laura; Weinert, Emily E

2017-08-18

Bacterial pathogens utilize numerous signals to identify the presence of their host and coordinate changes in gene expression that allow for infection. Within plant pathogens, these signals typically include small molecules and/or proteins from their plant hosts and bacterial quorum sensing molecules to ensure sufficient bacterial cell density for successful infection. In addition, bacteria use environmental signals to identify conditions when the host defenses are weakened and potentially to signal entry into an appropriate host/niche for infection. A globin coupled sensor protein (GCS), termed PccGCS, within the soft rot bacterium Pectobacterium carotovorum ssp. carotovorum WPP14 has been identified as an O 2 sensor and demonstrated to alter virulence factor excretion and control motility, with deletion of PccGCS resulting in decreased rotting of a potato host. Using small molecules that modulate bacterial growth and quorum sensing, PccGCS signaling also has been shown to modulate quorum sensing pathways, resulting in the PccGCS deletion strain being more sensitive to plant-derived phenolic acids, which can function as quorum sensing inhibitors, and exhibiting increased N-acylhomoserine lactone (AHL) production. These findings highlight a role for GCS proteins in controlling key O 2 -dependent phenotypes of pathogenic bacteria and suggest that modulating GCS signaling to limit P. carotovorum motility may provide a means to decrease rotting of plant hosts.

Novel N4-Like Bacteriophages of Pectobacterium atrosepticum.

PubMed

Buttimer, Colin; Hendrix, Hanne; Lucid, Alan; Neve, Horst; Noben, Jean-Paul; Franz, Charles; O'Mahony, Jim; Lavigne, Rob; Coffey, Aidan

2018-05-14

Pectobacterium atrosepticum is an economically important phytopathogen that is responsible for potato blackleg and soft rot, and for which current control strategies are limited. In this study, stem samples of potato crops exhibiting blackleg were taken from three farms in Co. Cork, Ireland, and they were found to be infected with P. atrosepticum . Three closely related bacteriophages (phages) that are specific to this phytopathogen were isolated and characterized, namely vB_PatP_CB1, vB_PatP_CB3, and vB_PatP_CB4 (abbreviated as CB1, CB3, and CB4). Both CB1 and CB3 were determined to infect 12 strains and CB4 10 strains of the 19 strains of P. atrosepticum tested. Morphology, latent periods, burst sizes, and their stability at various temperatures and pHs were also examined. Genome sequencing of the three phages revealed that they shared a minimum nucleotide identity of 93% with each other. Their genomes exhibited an Enquartavirinae genome organization, possessing several conserved proteins that were associated with phages of this group, like the type species Escherichia virus N4. Tandem electrospray ionization-mass spectrometry (ESI-MS/MS) allowed for the identification of ten structural proteins that form the virion of CB1, six that are conserved in phage N4. Biocontrol experiments demonstrated that the phages suppress soft rot formation upon co-inoculation with P. atrosepticum on whole tubers. The results of this study indicate that CB1 related phages could be good candidates for phage-based control.

Phylogenetic and population analyses of the invasive brown root-rot pathogen (Phellinus noxius) highlight the existence of at least two distinct populations

Treesearch

J. E. Stewart; N. Sahashi; T. Hattori; M. Akiba; Y. Ota; L. Shuey; R. L. Schlub; N. Atibalentia; F. Brooks; A. M. C. Tang; R. Y. C. Lam; M. W. K. Leung; L. M. Chu; H. S. Kwan; A. Mohd Farid; S. S. Lee; C. -L. Chung; H. -H. Lee; Y.- C. Huang; R. -F. Liou; J. -N. Tsai; P. G. Cannon; J. W. Hanna; N. B. Klopfenstein; M. -S. Kim

2017-01-01

Phellinus noxius (Corner) G. H. Cunn is a vastly destructive, fast-growing pathogen that affects a wide range of woody hosts in pan-tropical areas, including Asia, Australia, Africa, and Oceania (Ann et al. 2002). This invasive pathogen causes brown root-rot disease on cacao, coffee, and rubber, as well as diverse fruit, nut, ornamental, and other native/exotic trees,...

Etiology and Epidemiological Conditions Promoting Fusarium Root Rot in Sweetpotato.

PubMed

Scruggs, A C; Quesada-Ocampo, L M

2016-08-01

Sweetpotato production in the United States is limited by several postharvest diseases, and one of the most common is Fusarium root rot. Although Fusarium solani is believed to be the primary causal agent of disease, numerous other Fusarium spp. have been reported to infect sweetpotato. However, the diversity of Fusarium spp. infecting sweetpotato in North Carolina is unknown. In addition, the lack of labeled and effective fungicides for control of Fusarium root rot in sweetpotato creates the need for integrated strategies to control disease. Nonetheless, epidemiological factors that promote Fusarium root rot in sweetpotato remain unexplored. A survey of Fusarium spp. infecting sweetpotato in North Carolina identified six species contributing to disease, with F. solani as the primary causal agent. The effects of storage temperature (13, 18, 23, 29, and 35°C), relative humidity (80, 90, and 100%), and initial inoculum level (3-, 5-, and 7-mm-diameter mycelia plug) were examined for progression of Fusarium root rot caused by F. solani and F. proliferatum on 'Covington' sweetpotato. Fusarium root rot was significantly reduced (P < 0.05) at lower temperatures (13°C), low relative humidity levels (80%), and low initial inoculum levels for both pathogens. Sporulation of F. proliferatum was also reduced under the same conditions. Qualitative mycotoxin analysis of roots infected with one of five Fusarium spp. revealed the production of fumonisin B1 by F. proliferatum when infecting sweetpotato. This study is a step toward characterizing the etiology and epidemiology of Fusarium root rot in sweetpotato, which allows for improved disease management recommendations to limit postharvest losses to this disease.

Virulence of Three Cylindrocladium Species to Yellow-Poplar Seedlings

Treesearch

T. H. Filer

1970-01-01

Cylindrocladium crotalariae and C. scoparium caused severe root rot on potted yellow-poplar seedlings. They appeared to be equally virulent. C. floridanum caused necrosis only on feeder roots of the seedlings.

Molecular Characterization of Global Regulatory RNA Species That Control Pathogenicity Factors in Erwinia amylovora and Erwinia herbicola pv. gypsophilae†‡

PubMed Central

Ma, Weilei; Cui, Yaya; Liu, Yang; Dumenyo, C. Korsi; Mukherjee, Asita; Chatterjee, Arun K.

2001-01-01

rsmBEcc specifies a nontranslatable RNA regulator that controls exoprotein production and pathogenicity in soft rot-causing Erwinia carotovora subsp. carotovora. This effect of rsmBEcc RNA is mediated mostly by neutralizing the function of RsmAEcc, an RNA-binding protein of E. carotovora subsp. carotovora, which acts as a global negative regulator. To determine the occurrence of functional homologs of rsmBEcc in non-soft-rot-causing Erwinia species, we cloned the rsmB genes of E. amylovora (rsmBEa) and E. herbicola pv. gypsophilae (rsmBEhg). We show that rsmBEa in E. amylovora positively regulates extracellular polysaccharide (EPS) production, motility, and pathogenicity. In E. herbicola pv. gypsophilae, rsmBEhg elevates the levels of transcripts of a cytokinin (etz) gene and stimulates the production of EPS and yellow pigment as well as motility. RsmAEa and RsmAEhg have more than 93% identity to RsmAEcc and, like the latter, function as negative regulators by affecting the transcript stability of the target gene. The rsmB genes reverse the negative effects of RsmAEa, RsmAEhg, and RsmAEcc, but the extent of reversal is highest with homologous combinations of rsm genes. These observations and findings that rsmBEa and rsmBEhg RNA bind RsmAEcc indicate that the rsmB effect is channeled via RsmA. Additional support for this conclusion comes from the observation that the rsmB genes are much more effective as positive regulators in a RsmA+ strain of E. carotovora subsp. carotovora than in its RsmA− derivative. E. herbicola pv. gypsophilae produces a 290-base rsmB transcript that is not subject to processing. By contrast, E. amylovora produces 430- and 300-base rsmB transcripts, the latter presumably derived by processing of the primary transcript as previously noted with the transcripts of rsmBEcc. Southern blot hybridizations revealed the presence of rsmB homologs in E. carotovora, E. chrysanthemi, E. amylovora, E. herbicola, E. stewartii and E. rhapontici, as well as in other enterobacteria such as Escherichia coli, Salmonella enterica serovar Typhimurium, Serratia marcescens, Shigella flexneri, Enterobacter aerogenes, Klebsiella pneumoniae, Yersinia enterocolitica, and Y. pseudotuberculosis. A comparison of rsmB sequences from several of these enterobacterial species revealed a highly conserved 34-mer region which is predicted to play a role in positive regulation by rsmB RNA. PMID:11222584

Identification and characterization of Pestalotiopsis-like fungi related to grapevine diseases in China.

PubMed

Jayawardena, Ruvishika S; Zhang, Wei; Liu, Mei; Maharachchikumbura, Sajeewa S N; Zhou, Ying; Huang, JinBao; Nilthong, Somrudee; Wang, ZhongYue; Li, XingHong; Yan, JiYe; Hyde, Kevin D

2015-05-01

Pestalotiopsis-like fungi are an important plant pathogenic genus causing postharvest fruit rot and trunk diseases in grapevine in many countries. Pestalotiopsis-like fungi diseases were studied in vineyards in nine provinces across China. Multi-gene (ITS, β-tubulin and tef1) analysis coupled with morphology showed that a Neopestalotiopsis sp. and Pestalotiopsis trachicarpicola are associated in causing grapevine fruit rot and trunk diseases in China. Pestalotiopsis trachicarpicola is reported as the causative agent of grapevine diseases in the world for the first time. Neopestalotiopsis sp. caused significantly longer lesions than the other taxon present. This study represents the first attempt to identify and characterize the Pestalotiopsis-like fungi causing grapevine diseases in China using both morphological and molecular approaches. Copyright © 2014 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.

Rice-Infecting Pseudomonas Genomes Are Highly Accessorized and Harbor Multiple Putative Virulence Mechanisms to Cause Sheath Brown Rot.

PubMed

Quibod, Ian Lorenzo; Grande, Genelou; Oreiro, Eula Gems; Borja, Frances Nikki; Dossa, Gerbert Sylvestre; Mauleon, Ramil; Cruz, Casiana Vera; Oliva, Ricardo

2015-01-01

Sheath rot complex and seed discoloration in rice involve a number of pathogenic bacteria that cannot be associated with distinctive symptoms. These pathogens can easily travel on asymptomatic seeds and therefore represent a threat to rice cropping systems. Among the rice-infecting Pseudomonas, P. fuscovaginae has been associated with sheath brown rot disease in several rice growing areas around the world. The appearance of a similar Pseudomonas population, which here we named P. fuscovaginae-like, represents a perfect opportunity to understand common genomic features that can explain the infection mechanism in rice. We showed that the novel population is indeed closely related to P. fuscovaginae. A comparative genomics approach on eight rice-infecting Pseudomonas revealed heterogeneous genomes and a high number of strain-specific genes. The genomes of P. fuscovaginae-like harbor four secretion systems (Type I, II, III, and VI) and other important pathogenicity machinery that could probably facilitate rice colonization. We identified 123 core secreted proteins, most of which have strong signatures of positive selection suggesting functional adaptation. Transcript accumulation of putative pathogenicity-related genes during rice colonization revealed a concerted virulence mechanism. The study suggests that rice-infecting Pseudomonas causing sheath brown rot are intrinsically diverse and maintain a variable set of metabolic capabilities as a potential strategy to occupy a range of environments.

Introgression of Black Rot Resistance from Brassica carinata to Cauliflower (Brassica oleracea botrytis Group) through Embryo Rescue

PubMed Central

Sharma, Brij B.; Kalia, Pritam; Singh, Dinesh; Sharma, Tilak R.

2017-01-01

Black rot caused by Xanthomonas campestris pv. campestris (Xcc) is a very important disease of cauliflower (Brassica oleracea botrytis group) resulting into 10–50% yield losses every year. Since there is a dearth of availability of resistance to black rot disease in B. oleracea (C genome), therefore exploration of A and B genomes was inevitable as they have been reported to be potential reservoirs of gene(s) for resistance to black rot. To utilize these sources, interspecific hybrid and backcross progeny (B1) were generated between cauliflower “Pusa Sharad” and Ethiopian mustard “NPC-9” employing in vitro embryo rescue technique. Direct ovule culture method was better than siliqua culture under different temperature regime periods. Hybridity testing of F1 inter-specific plants was carried out using co-dominant SSR marker and Brassica B and C genome-specific (DB and DC) primers. Meiosis in the di-genomic (BCC) interspecific hybrid of B. oleracea botrytis group (2n = 18, CC) × B. carinata (2n = 4x = 34, BBCC) was higly disorganized and cytological analysis of pollen mother cells revealed chromosomes 2n = 26 at metaphase-I. Fertile giant pollen grain formation was observed frequently in interspecific F1 hybrid and BC1 plants. The F1 inter-specific plants were found to be resistant to Xcc race 1. Segregation distortion was observed in BC1 generation for black rot resistance and different morphological traits. The At1g70610 marker analysis confirmed successful introgression of black rot resistance in interspecific BC1 population. This effort will go a long way in pyramiding gene(s) for resistance against black rot in Cole crops, especially cauliflower and cabbage for developing durable resistance, thus minimize dependency on bactericides. PMID:28769959

Introgression of Black Rot Resistance from Brassica carinata to Cauliflower (Brassica oleracea botrytis Group) through Embryo Rescue.

PubMed

Sharma, Brij B; Kalia, Pritam; Singh, Dinesh; Sharma, Tilak R

2017-01-01

Black rot caused by Xanthomonas campestris pv. campestris ( Xcc ) is a very important disease of cauliflower ( Brassica oleracea botrytis group) resulting into 10-50% yield losses every year. Since there is a dearth of availability of resistance to black rot disease in B. oleracea (C genome), therefore exploration of A and B genomes was inevitable as they have been reported to be potential reservoirs of gene(s) for resistance to black rot. To utilize these sources, interspecific hybrid and backcross progeny (B 1 ) were generated between cauliflower "Pusa Sharad" and Ethiopian mustard "NPC-9" employing in vitro embryo rescue technique. Direct ovule culture method was better than siliqua culture under different temperature regime periods. Hybridity testing of F 1 inter-specific plants was carried out using co-dominant SSR marker and Brassica B and C genome-specific (DB and DC) primers. Meiosis in the di-genomic (BCC) interspecific hybrid of B. oleracea botrytis group (2 n = 18, CC) × B. carinata (2 n = 4x = 34, BBCC) was higly disorganized and cytological analysis of pollen mother cells revealed chromosomes 2 n = 26 at metaphase-I. Fertile giant pollen grain formation was observed frequently in interspecific F 1 hybrid and BC 1 plants. The F 1 inter-specific plants were found to be resistant to Xcc race 1. Segregation distortion was observed in BC 1 generation for black rot resistance and different morphological traits. The At1g70610 marker analysis confirmed successful introgression of black rot resistance in interspecific BC 1 population. This effort will go a long way in pyramiding gene(s) for resistance against black rot in Cole crops, especially cauliflower and cabbage for developing durable resistance, thus minimize dependency on bactericides.

Candidate gene association mapping of Sclerotinia stalk rot resistance in sunflower (Helianthus annuus L.) uncovers the importance of COI1 homologs.

PubMed

Talukder, Zahirul I; Hulke, Brent S; Qi, Lili; Scheffler, Brian E; Pegadaraju, Venkatramana; McPhee, Kevin; Gulya, Thomas J

2014-01-01

Functional markers for Sclerotinia basal stalk rot resistance in sunflower were obtained using gene-level information from the model species Arabidopsis thaliana. Sclerotinia stalk rot, caused by Sclerotinia sclerotiorum, is one of the most destructive diseases of sunflower (Helianthus annuus L.) worldwide. Markers for genes controlling resistance to S. sclerotiorum will enable efficient marker-assisted selection (MAS). We sequenced eight candidate genes homologous to Arabidopsis thaliana defense genes known to be associated with Sclerotinia disease resistance in a sunflower association mapping population evaluated for Sclerotinia stalk rot resistance. The total candidate gene sequence regions covered a concatenated length of 3,791 bp per individual. A total of 187 polymorphic sites were detected for all candidate gene sequences, 149 of which were single nucleotide polymorphisms (SNPs) and 38 were insertions/deletions. Eight SNPs in the coding regions led to changes in amino acid codons. Linkage disequilibrium decay throughout the candidate gene regions declined on average to an r (2) = 0.2 for genetic intervals of 120 bp, but extended up to 350 bp with r (2) = 0.1. A general linear model with modification to account for population structure was found the best fitting model for this population and was used for association mapping. Both HaCOI1-1 and HaCOI1-2 were found to be strongly associated with Sclerotinia stalk rot resistance and explained 7.4 % of phenotypic variation in this population. These SNP markers associated with Sclerotinia stalk rot resistance can potentially be applied to the selection of favorable genotypes, which will significantly improve the efficiency of MAS during the development of stalk rot resistant cultivars.

A survey of pre-harvest ear rot diseases of maize and associated mycotoxins in south and central Zambia.

PubMed

Mukanga, Mweshi; Derera, John; Tongoona, Pangirayi; Laing, Mark D

2010-07-15

Maize ear rots reduce grain yield and quality with implication on food security and health. Some of the pathogenic fungi produce mycotoxins in maize grain posing a health risk to humans and livestock. Unfortunately, the levels of ear rot and mycotoxin infection in grain produced by subsistence farmers in sub-Saharan countries are not known. A survey was thus conducted to determine the prevalence of the ear rot problem and levels of mycotoxins in maize grain. A total of 114 farmsteads were randomly sampled from 11 districts in Lusaka and southern provinces in Zambia during 2006. Ten randomly picked cobs were examined per farmstead and the ear rot disease incidence and severity were estimated on site. This was followed by the standard seed health testing procedures for fungal isolation in the laboratory. Results indicated that the dominant ear rots were caused by Fusarium and Stenocarpella. Incidence of Fusarium verticillioides ranged from 2 to 21%, whereas that of Stenocarpella maydis reached 37% on ear rot diseased maize grain. In addition, 2-7% F. verticillioides, and 3-18% Aspergillus flavus, respectively, were recovered from seemingly healthy maize grain. The mean rank of fungal species, from highest to lowest, was F. verticillioides, S. maydis, A. flavus, Fusarium graminearum, Aspergillus niger, Penicillium spp., Botrydiplodia spp., and Cladosporium spp. The direct competitive ELISA-test indicated higher levels of fumonisins than aflatoxins in pre-harvest maize grain samples. The concentration of fumonisins from six districts, and aflatoxin from two districts, was 10-fold higher than 2 ppm and far higher than 2 ppb maximum daily intake recommended by the FAO/WHO. The study therefore suggested that subsistence farmers and consumers in this part of Zambia, and maybe also in similar environments in sub-Saharan Africa, might be exposed to dangerous levels of mycotoxins due to the high levels of ear rot infections in maize grain. 2010 Elsevier B.V. All rights reserved.

Neuroprotective potential of ferulic acid in the rotenone model of Parkinson’s disease

PubMed Central

Ojha, Shreesh; Javed, Hayate; Azimullah, Sheikh; Abul Khair, Salema B; Haque, M Emdadul

2015-01-01

Parkinson’s disease (PD) is a chronic, progressive, and the second most common form of neurodegenerative disorders. In order to explore novel agents for the treatment of PD, in the current study, we have evaluated the neuroprotective efficacy of ferulic acid (FA) using rotenone (ROT)-induced rat model of PD. ROT was administered 2.5 mg/kg body weight to male Wistar rats for 4 weeks to induce the PD. Since PD is progressive and chronic in nature, the paradigm for evaluating FA was based on chronic administration for 4 weeks at the dose of 50 mg/kg, 30 minutes prior to ROT administration. ROT administration caused significant reduction in endogenous antioxidants such as superoxide dismutase, catalase, and glutathione. ROT challenge-induced lipid peroxidation evidenced by increased malondialdehyde following perturbation of antioxidant defense. Apart from oxidative stress, ROT also activated proinflammatory cytokines and enhanced inflammatory mediators such as cyclooxygenase-2 and inducible nitric oxide synthase. The immunofluorescence analysis revealed a significant increase in the number of activated microglia and astrocytes accompanied by a significant loss of dopamine (DA) neurons in the substantia nigra pars compacta area upon ROT injection. However, treatment with FA rescued DA neurons in substantia nigra pars compacta area and nerve terminals in the striatum from the ROT insult. FA treatment also restored antioxidant enzymes, prevented depletion of glutathione, and inhibited lipid peroxidation. Following treatment with FA, the inflammatory mediators such as cyclooxygenase-2 and inducible nitric oxide synthase and proinflammatory cytokines were also reduced. Further, the results were supported by a remarkable reduction of Iba-1 and GFAP hyperactivity clearly suggests attenuation of microglial and astrocytic activation. Results of our study suggest that FA has promising neuroprotective effect against degenerative changes in PD, and the protective effects are mediated through its antioxidant and anti-inflammatory properties. PMID:26504373

Integrated control of white rot disease on beans caused by Sclerotinia sclerotiorum using Contans® and reduced fungicides application.

PubMed

Elsheshtawi, Mohamed; Elkhaky, Maged T; Sayed, Shaban R; Bahkali, Ali H; Mohammed, Arif A; Gambhir, Dikshit; Mansour, Aref S; Elgorban, Abdallah M

2017-02-01

This study was conducted to determine the compatibility of Contans® ( Coniothyrium minitans ) with fungicides against Sclerotinia sclerotiorum . Results showed that both Contans® and Topsin® significantly reduced the disease incidence caused by S. sclerotiorum by 90% and 95% survival plants, respectively when they were individually applied and compared to control. While, soil application of Contans® and Sumisclex mixture was the most effective in suppressing the white rot disease incidence that produced 100% survival plants, application of C. minitans combined with the reduced doses of fungicides would be advantageous in saving labor cost, thus increasing production efficiency of bean.

Identification and mycotoxigenic capacity of fungi associated with pre- and postharvest fruit rots of pomegranates in Greece and Cyprus.

PubMed

Kanetis, Loukas; Testempasis, Stefanos; Goulas, Vlasios; Samuel, Stylianos; Myresiotis, Charalampos; Karaoglanidis, George S

2015-09-02

Pre- and postharvest fruit rots of fungal origin are an important burden for the pomegranate industry worldwide, affecting the produce both quantitatively and qualitatively. During 2013, local orchards were surveyed and 280 fungal isolates from Greece (GR) and Cyprus (CY) were collected from pomegranates exhibiting preharvest rot symptoms, and additional 153 isolates were collected postharvest from cold-stored fruit in GR. Molecular identification revealed that preharvest pomegranate fruit rots were caused predominately by species of the genera Aspergillus (Aspergillus niger and Aspergillus tubingensis) and Alternaria (Alternaria alternata, Alternaria tenuissima, and Alternaria arborescens). By contrast, postharvest fruit rots were caused mainly by Botrytis spp. and to a lesser extent by isolates of Pilidiella granati and Alternaria spp. Considering that a significant quota of the fungal species found in association with pomegranate fruit rots are known for their mycotoxigenic capacity in other crop systems, their mycotoxin potential was examined. Alternariol (AOH), alternariol monomethyl-ether (AME) and tentoxin (TEN) production was estimated among Alternaria isolates, whereas ochratoxin A (OTA) and fumonisin B2 (FB2) production was assessed within the black aspergilli identified. Overall in both countries, 89% of the Alternaria isolates produced AOH and AME in vitro, while TEN was produced only by 43.9%. In vivo production of AOH and AME was restricted to 54.2% and 31.6% of the GR and CY isolates, respectively, while none of the isolates produced TEN in vivo. Among black aspergilli 21.7% of the GR and 17.8% of the CY isolates produced OTA in vitro, while in vivo OTA was detected in 8.8% of the isolates from both countries. FB2 was present in vitro in 42.0% of the GR and 22.2% of the CY isolates, while in vivo the production was limited to 27.5% and 4.5% of the GR and the CY isolates, respectively. Our data imply that mycotoxigenic Alternaria and Aspergillus species not only constitute a significant subset of the fungal population associated with pomegranate fruit rots responsible for fruit deterioration, but also pose a potential health risk factor for consumers of pomegranate-based products. Copyright © 2015 Elsevier B.V. All rights reserved.

Evaluation of Muscodor suthepensis strain CMU-Cib462 as a postharvest biofumigant for tangerine fruit rot caused by Penicillium digitatum.

PubMed

Suwannarach, Nakarin; Bussaban, Boonsom; Nuangmek, Wipornpan; Pithakpol, Wasna; Jirawattanakul, Bantoon; Matsui, Kenji; Lumyong, Saisamorn

2016-01-15

This study investigated both the in vitro and in vivo biofumigant ability of the endophytic fungus Muscodor suthepensis CMU-Cib462 to control Penicillium digitatum, the main cause of tangerine fruit rot. Volatile compounds from M. suthepensis inhibited mycelial growth of the pathogen. The most abundant compound was 2-methylpropanoic acid, followed by 3-methylbutan-1-ol. They showed median effective doses (ED50) on P. digitatum growth of 74.91 ± 0.73 and 250.29 ± 0.29 µL L(-1) airspace respectively. Rye grain was found to be a suitable solid medium for M. suthepensis inoculum production. The results indicated that mycofumigation with a 30 g rye grain culture of M. suthepensis for 12 h controlled tangerine fruit rot. The percentage weight loss and soluble solids concentration of fumigated tangerines were similar to those of non-infected and non-fumigated fruits. Muscodor suthepensis has potential as a biofumigant for controlling postharvest disease of tangerine fruit. © 2015 Society of Chemical Industry.

Insights into molecular and metabolic events associated with fruit response to post-harvest fungal pathogens

PubMed Central

Alkan, Noam; Fortes, Ana M.

2015-01-01

Due to post-harvest losses more than 30% of harvested fruits will not reach the consumers’ plate. Fungal pathogens play a key role in those losses, as they cause most of the fruit rots and the customer complaints. Many of the fungal pathogens are already present in the unripe fruit but remain quiescent during fruit growth until a particular phase of fruit ripening and senescence. The pathogens sense the developmental change and switch into the devastating necrotrophic life style that causes fruit rotting. Colonization of unripe fruit by the fungus initiates defensive responses that limit fungal growth and development. However, during fruit ripening several physiological processes occur that correlate with increased fruit susceptibility. In contrast to plant defenses in unripe fruit, the defense posture of ripe fruit entails a different subset of defense responses that will end with fruit rotting and losses. This review will focus on several aspects of molecular and metabolic events associated with fleshy fruit responses induced by post-harvest fungal pathogens during fruit ripening. PMID:26539204

Brown Rot-Type Fungal Decomposition of Sorghum Bagasse: Variable Success and Mechanistic Implications

DOE PAGES

Presley, Gerald N.; Ndimba, Bongani K.; Schilling, Jonathan S.

2018-01-01

Sweet sorghum is a promising crop for a warming, drying African climate, and basic information is lacking on conversion pathways for its lignocellulosic residues (bagasse). Brown rot wood-decomposer fungi use carbohydrate-selective pathways that, when assessed on sorghum, a grass substrate, can yield information relevant to both plant biomass conversion and fungal biology. In testing sorghum decomposition by brown rot fungi ( Gloeophyllum trabeum , Serpula lacrymans ), we found that G. trabeum readily degraded sorghum, removing xylan prior to removing glucan. Serpula lacrymans , conversely, caused little decomposition. Ergosterol (fungal biomarker) and protein levels were similar for both fungi, butmore » S. lacrymans produced nearly 4x lower polysaccharide-degrading enzyme specific activity on sorghum than G. trabeum , perhaps a symptom of starvation. Linking this information to genome comparisons including other brown rot fungi known to have a similar issue regarding decomposing grasses (Postia placenta, Fomitopsis pinicola) suggested that a lack of CE 1 feruloyl esterases as well as low xylanase activity in S. lacrymans (3x lower than in G. trabeum ) may hinder S. lacrymans , P. placenta, and F. pinicola when degrading grass substrates. These results indicate variability in brown rot mechanisms, which may stem from a differing ability to degrade certain lignin-carbohydrate complexes.« less

Brown Rot-Type Fungal Decomposition of Sorghum Bagasse: Variable Success and Mechanistic Implications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Presley, Gerald N.; Ndimba, Bongani K.; Schilling, Jonathan S.

Sweet sorghum is a promising crop for a warming, drying African climate, and basic information is lacking on conversion pathways for its lignocellulosic residues (bagasse). Brown rot wood-decomposer fungi use carbohydrate-selective pathways that, when assessed on sorghum, a grass substrate, can yield information relevant to both plant biomass conversion and fungal biology. In testing sorghum decomposition by brown rot fungi ( Gloeophyllum trabeum , Serpula lacrymans ), we found that G. trabeum readily degraded sorghum, removing xylan prior to removing glucan. Serpula lacrymans , conversely, caused little decomposition. Ergosterol (fungal biomarker) and protein levels were similar for both fungi, butmore » S. lacrymans produced nearly 4x lower polysaccharide-degrading enzyme specific activity on sorghum than G. trabeum , perhaps a symptom of starvation. Linking this information to genome comparisons including other brown rot fungi known to have a similar issue regarding decomposing grasses (Postia placenta, Fomitopsis pinicola) suggested that a lack of CE 1 feruloyl esterases as well as low xylanase activity in S. lacrymans (3x lower than in G. trabeum ) may hinder S. lacrymans , P. placenta, and F. pinicola when degrading grass substrates. These results indicate variability in brown rot mechanisms, which may stem from a differing ability to degrade certain lignin-carbohydrate complexes.« less

Diplodiatoxin, chaetoglobosins, and diplonine associated with a field outbreak of Stenocarpella ear rot in Illinois.

PubMed

Rogers, Kristina D; Cannistra, Joseph C; Gloer, James B; Wicklow, Donald T

2014-05-01

Stenocarpella maydis causes a fungal dry-rot of maize ears and is associated with diplodiosis, a neuromycotoxicosis in cattle grazing harvested maize fields in southern Africa and Argentina. There have been no reports of Stenocarpella metabolites in maize crop residues. Chemical investigations of S. maydis-infected grain from ears exhibiting different levels of ear rot severity following a 2010 field outbreak of Stenocarpella ear rot in Illinois led to the detection of diplodiatoxin and chaetoglobosins M and O as major components in the ethyl acetate extracts by LC-MS. Following post-harvest moist incubation of the S. maydis-infected grain, the amounts of each compound increased (approx. tenfold) and chaetoglobosin K was detected as a dominant toxin. In separate (1)H NMR-based analyses, the neurotoxin diplonine was detected as a minor component in methanol extracts of S. maydis-infected grain as well as cultures of S. maydis isolates from Midwest corn. Proline betaine (=stachydrine) and glycine betaine were also detected in these extracts as major components. This constitutes the first report of chaetoglobosin M, chaetoglobosin O, proline betaine, or glycine betaine from S. maydis, and the first record of diplodiatoxin, diplonine, proline betaine, glycine betaine, or chaetoglobosins M, O, or K being associated with a natural field outreak of S. maydis ear rot.

Rapid polyether cleavage via extracellular one-electron oxidation by a brown-rot basidiomycete.

PubMed

Kerem, Z; Bao, W; Hammel, K E

1998-09-01

Fungi that cause brown rot of wood are essential biomass recyclers and also the principal agents of decay in wooden structures, but the extracellular mechanisms by which they degrade lignocellulose remain unknown. To test the hypothesis that brown-rot fungi use extracellular free radical oxidants as biodegradative tools, Gloeophyllum trabeum was examined for its ability to depolymerize an environmentally recalcitrant polyether, poly(ethylene oxide) (PEO), that cannot penetrate cell membranes. Analyses of degraded PEOs by gel permeation chromatography showed that the fungus cleaved PEO rapidly by an endo route. 13C NMR analyses of unlabeled and perdeuterated PEOs recovered from G. trabeum cultures showed that a major route for depolymerization was oxidative C---C bond cleavage, a reaction diagnostic for hydrogen abstraction from a PEO methylene group by a radical oxidant. Fenton reagent (Fe(II)/H2O2) oxidized PEO by the same route in vitro and therefore might account for PEO biodegradation if it is produced by the fungus, but the data do not rule out involvement of less reactive radicals. The reactivity and extrahyphal location of this PEO-degrading system suggest that its natural function is to participate in the brown rot of wood and that it may enable brown-rot fungi to degrade recalcitrant organopollutants.

Protection of turmeric plants from rhizome rot disease under field conditions by β-D-glucan nanoparticle.

PubMed

Anusuya, Sathiyanarayanan; Sathiyabama, Muthukrishnan

2015-01-01

The rhizome rot caused by Pythium aphanidermatum is one of the most devastating diseases of the turmeric crop. Fungicides are unable to control the rapidly evolving P. aphanidermatum and new control strategies are urgently needed. This study examined the effect of β-d-glucan nanoparticles (GNP) in turmeric plants under field condition by the foliar spray method. Enhanced plant growth, rhizome yield, and curcumin content demonstrate the positive effect of the GNP on turmeric plants. Rapid activation of various defense enzymes was also observed in leaves and rhizomes of treated plants. GNP-treated plants showed a decreased rot incidence. It may be possible that increased defense enzymes might have played a role in reducing the colonization of pathogen. Copyright © 2015 Elsevier B.V. All rights reserved.

Laminated root rot in a western Washington plantation: 8-year mortality and growth of Douglas-fir as related to infected stumps, tree density, and fertilization.

Treesearch

Richard E. Miller; Timothy B. Harrington; Walter G. Thies; Jeff. Madsen

2006-01-01

A 4-year-old Douglas-fir plantation in the western Washington Cascades was monitored for 8 years after fertilization with potassium (K), nitrogen (N), and K+N to determine fertilizer effects on rates of mortality from laminated root rot (LRR) and other causes relative to a nonfertilized control. Each element was applied at a rate of 300 lb/acre on and around 0.2-acre...

Development and Evaluation of Glycine max Germplasm Lines with Quantitative Resistance to Sclerotinia sclerotiorum

PubMed Central

McCaghey, Megan; Willbur, Jaime; Ranjan, Ashish; Grau, Craig R.; Chapman, Scott; Diers, Brian; Groves, Carol; Kabbage, Mehdi; Smith, Damon L.

2017-01-01

Sclerotinia sclerotiorum, the causal agent of Sclerotinia stem rot, is a devastating fungal pathogen of soybean that can cause significant yield losses to growers when environmental conditions are favorable for the disease. The development of resistant varieties has proven difficult. However, poor resistance in commercial cultivars can be improved through additional breeding efforts and understanding the genetic basis of resistance. The objective of this project was to develop soybean germplasm lines that have a high level of Sclerotinia stem rot resistance to be used directly as cultivars or in breeding programs as a source of improved Sclerotinia stem rot resistance. Sclerotinia stem rot-resistant soybean germplasm was developed by crossing two sources of resistance, W04-1002 and AxN-1-55, with lines exhibiting resistance to Heterodera glycines and Cadophora gregata in addition to favorable agronomic traits. Following greenhouse evaluations of 1,076 inbred lines derived from these crosses, 31 lines were evaluated for resistance in field tests during the 2014 field season. Subsequently, 11 Sclerotinia stem rot resistant breeding lines were moved forward for field evaluation in 2015, and seven elite breeding lines were selected and evaluated in the 2016 field season. To better understand resistance mechanisms, a marker analysis was conducted to identify quantitative trait loci linked to resistance. Thirteen markers associated with Sclerotinia stem rot resistance were identified on chromosomes 15, 16, 17, 18, and 19. Our markers confirm previously reported chromosomal regions associated with Sclerotinia stem rot resistance as well as a novel region of chromosome 16. The seven elite germplasm lines were also re-evaluated within a greenhouse setting using a cut petiole technique with multiple S. sclerotiorum isolates to test the durability of physiological resistance of the lines in a controlled environment. This work presents a novel and comprehensive classical breeding method for selecting lines with physiological resistance to Sclerotinia stem rot and a range of agronomic traits. In these studies, we identify four germplasm lines; 91–38, 51–23, SSR51–70, and 52–82B exhibiting a high level of Sclerotinia stem rot resistance combined with desirable agronomic traits, including high protein and oil contents. The germplasm identified in this study will serve as a valuable source of physiological resistance to Sclerotinia stem rot that could be improved through further breeding to generate high-yielding commercial soybean cultivars. PMID:28912790

Changes in structural and chemical components of wood delignified by fungi

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blanchette, R.A.; Otjen, L.; Effland, M.J.

1985-01-01

Cerrena unicolor, Ganoderma applanatum, Ischnoderma resinosum and Poria medulla-panis were associated with birch (Betula papyrifera) wood that had been selectively delignified in the forest. Preferential lignin degradation was not uniformly distributed throughout the decayed wood. A typical white rot causing a simultaneous removal of all cell wall components was also present. In the delignified wood, 95 to 98% of the lignin was removed as well as substantial amounts of hemicelluloses. Scanning and transmission electron microscopy were used to identify the micromorphological and ultrastructural changes that occurred in the cells during degradation. In delignified areas the compound middle lamella was extensivelymore » degraded causing a defibration of cells. The secondary wall, especially the S2 layer, remained relatively unaltered. In simultaneously white-rotted wood all cell wall layers were progressively removed from the lumen toward the middle lamella causing erosion troughs or holes to form. Large voids filled with fungal mycelia resulted from a coalition of degraded areas. Birch wood decayed in laboratory soil-block tests was also intermittently delignified, selective delignification, sparsely distributed throughout the wood, and a simultaneous rot resulting in the removal of all cell wall components were evident. SEM appears to be an appropriate technique for examining selectively delignified decayed wood. 30 references.« less

Adaptation to new nutritional environments: larval performance, foraging decisions, and adult oviposition choices in Drosophila suzukii.

PubMed

Silva-Soares, Nuno F; Nogueira-Alves, A; Beldade, P; Mirth, Christen Kerry

2017-06-07

Understanding how species adapt to new niches is a central issue in evolutionary ecology. Nutrition is vital for the survival of all organisms and impacts species fitness and distribution. While most Drosophila species exploit rotting plant parts, some species have diversified to use ripe fruit, allowing earlier colonization. The decomposition of plant material is facilitated by yeast colonization and proliferation. These yeasts serve as the main protein source for Drosophila larvae. This dynamic rotting process entails changes in the nutritional composition of the food and other properties, and animals feeding on material at different stages of decay are expected to have behavioural and nutritional adaptations. We compared larval performance, feeding behaviour and adult oviposition site choice between the ripe fruit colonizer and invasive pest Drosophila suzukii, and a closely-related rotting fruit colonizer, Drosophila biarmipes. Through the manipulation of protein:carbohydrate ratios in artificial diets, we found that D. suzukii larvae perform better at lower protein concentrations and consume less protein rich diets relative to D. biarmipes. For adult oviposition, these species differed in preference for substrate hardness, but not for the substrate nutritional composition. Our findings highlight that rather than being an exclusive specialist on ripe fruit, D. suzukii's adaptation to use ripening fruit allow it to colonize a wider range of food substrates than D. biarmipes, which is limited to soft foods with higher protein concentrations. Our results underscore the importance of nutritional performance and feeding behaviours in the colonization of new food niches.

Development of biocontrol agents from food microbial isolates for controlling post-harvest peach brown rot caused by Monilinia fructicola.

PubMed

Zhou, Ting; Schneider, Karin E; Li, Xiu-Zhen

2008-08-15

An unconventional strategy of screening food microbes for biocontrol activity was used to develop biocontrol agents for controlling post-harvest peach brown rot caused by Monilinia fructicola. Forty-four microbial isolates were first screened for their biocontrol activity on apple fruit. Compared with the pathogen-only check, seven of the 44 isolates reduced brown rot incidence by >50%, including four bacteria: Bacillus sp. C06, Lactobacillus sp. C03-b and Bacillus sp. T03-c, Lactobacillus sp. P02 and three yeasts: Saccharomyces delbrueckii A50, S. cerevisiae YE-5 and S. cerevisiae A41. Eight microbial isolates were selected for testing on peaches by wound co-inoculation with mixtures of individual microbial cultures and conidial suspension of M. fructicola. Only two of them showed significant biocontrol activity after five days of incubation at 22 degrees C. Bacillus sp. C06 suppressed brown rot incidence by 92% and reduced lesion diameter by 88% compared to the pathogen-only check. Bacillus sp.T03-c reduced incidence and lesion diameter by 40% and 62%, respectively. The two isolates were compared with Pseudomonas syringae MA-4, a biocontrol agent for post-harvest peach diseases, by immersing peaches in an aliquot containing individual microbial isolates and the pathogen conidia. Treatments with isolates MA-4, C06 and T03-c significantly controlled brown rot by 91, 100, and 100% respectively. However, only isolates MA-4 and C06 significantly reduced brown rot by 80% and 15%, respectively when bacterial cells alone were applied. On naturally infected peaches, both the bacterial culture and its cell-free filtrate of the isolate C06 significantly controlled peach decay resulting in 77 and 90% reduction, respectively, whereas the treatment using only the bacterial cells generally had no effect. Isolate C06 is a single colony isolate obtained from a mesophilic cheese starter, and has been identified belonging to Bacillus amyloliquefaciens. The results have clearly demonstrated that isolate C06 has a great potential for being developed into a biocontrol agent.

Quantification of the changes in potent wine odorants as induced by bunch rot (Botrytis cinerea) and powdery mildew (Erysiphe necator)

NASA Astrophysics Data System (ADS)

Lopez Pinar, Angela; Rauhut, Doris; Ruehl, Ernst; Buettner, Andrea

2017-08-01

Fungal infections are detrimental for viticulture since they may reduce harvest yield and wine quality. This study aimed to characterize the effects of bunch rot and powdery mildew on wine aroma by quantification of representative aroma compounds using Stable Isotope Dilution Analysis (SIDA). For this purpose, samples affected to a high degree by each fungus were compared with a healthy sample in each case; to this aim, the respective samples were collected and processed applying identical conditions. Thereby, the effects of bunch rot were studied in three different grape varieties: White Riesling, Red Riesling and Gewürztraminer whereas the influence of powdery mildew was studied on the hybrid Gm 8622-3. Analyses revealed that both fungal diseases caused significant changes in the concentration of most target compounds. Thereby, the greatest effects were increases in the concentration of phenylacetic acid, acetic acid and γ-decalactone for both fungi and all grape varieties. Regarding other compounds, however, inconsistent effects of bunch rot were observed for the three varieties studied.

Molecular identification of Neofabraea species associated with bull's-eye rot on apple using rolling-circle amplification of partial EF-1α sequence.

PubMed

Lin, Huijiao; Jiang, Xiang; Yi, Jianping; Wang, Xinguo; Zuo, Ranling; Jiang, Zide; Wang, Weifang; Zhou, Erxun

2018-01-01

A rolling-circle amplification (RCA) method with padlock probes targeted on EF-1α regions was developed for rapid detection of apple bull's-eye rot pathogens, including Neofabraea malicorticis, N. perennans, N. kienholzii, and N. vagabunda (synonym: N. alba). Four padlock probes (PLP-Nm, PLP-Np, PLP-Nk, and PLP-Nv) were designed and tested against 28 samples, including 22 BER pathogen cultures, 4 closely related species, and 2 unrelated species that may cause serious apple decays. The assay successfully identified all the bull's-eye rot pathogenic fungi at the level of species, while no cross-reaction was observed in all target species and no false-positive reaction was observed with all strains used for reference. This study showed that the use of padlock probes and the combination of probe signal amplification by RCA provided an effective and sensitive method for the rapid identification of Neofabraea spp. The method could therefore be a useful tool for monitoring bull's-eye rot pathogens in port quarantine and orchard epidemiological studies.

Heterobasidion (Fornes) Annosum Incidence in Pre-Commercially Thinned Coastal Washington Western Hemlock Stands

Treesearch

Willis R. Littke; John E. Browning

1989-01-01

Heterobasidion annosum infects western hemlock (Tsuga heterophylla) and causes a root and butt-rot disease. A disease survey was initiated in thinned Southwestern Washington hemlock stands to determine current disease incidence caused by H. annosum.

21 CFR 520.2240b - Sulfaethoxypyridazine tablets.

Code of Federal Regulations, 2012 CFR

2012-04-01

... (pneumonia, shipping fever), foot rot, calf scours; as adjunctive therapy in septicemia accompanying mastitis... and pneumonia) caused by sulfonamide-susceptible pathogens (E. coli, streptococci, staphylococci...

21 CFR 520.2240b - Sulfaethoxypyridazine tablets.

Code of Federal Regulations, 2013 CFR

2013-04-01

... (pneumonia, shipping fever), foot rot, calf scours; as adjunctive therapy in septicemia accompanying mastitis... and pneumonia) caused by sulfonamide-susceptible pathogens (E. coli, streptococci, staphylococci...

21 CFR 520.2240b - Sulfaethoxypyridazine tablets.

Code of Federal Regulations, 2014 CFR

2014-04-01

... (pneumonia, shipping fever), foot rot, calf scours; as adjunctive therapy in septicemia accompanying mastitis... and pneumonia) caused by sulfonamide-susceptible pathogens (E. coli, streptococci, staphylococci...

Isolation of Dickeya dadantii strains from potato disease and biocontrol by their bacteriophages.

PubMed

Soleimani-Delfan, Abbas; Etemadifar, Zahra; Emtiazi, Giti; Bouzari, Majid

2015-01-01

One of the most economically important bacterial pathogens of plants and plant products is Dickeya dadantii. This bacterium causes soft rot disease in tubers and other parts of the potato and other plants of the Solanaceae family. The application of restricted host range bacteriophages as biocontrol agents has recently gained widespread interest. This study purposed to isolate the infectious agent of the potato and evaluate its biocontrol by bacteriophages. Two phytopathogenic strains were isolated from infected potatoes, identified based on biochemical and 16S rRNA gene sequencing, and submitted to GenBank as D. dadantii strain pis3 (accession no. HQ423668) and D. dadantii strain sip4 (accession no. HQ423669). Their bacteriophages were isolated from Caspian Sea water by enriching the water filtrate with D. dadantii strains as hosts using spot or overlay methods. On the basis of morphotypes, the isolated bacteriophages were identified as members of the Myoviridae and Siphoviridae families and could inhibit the growth of antibiotic resistant D. dadantii strains in culture medium. Moreover, in Dickeya infected plants treated with bacteriophage, no disease progression was detected. No significant difference was seen between phage-treated and control plants. Thus, isolated bacteriophages can be suggested for the biocontrol of plant disease caused by Dickeya strains.

Inactivation of pecS restores the virulence of mutants devoid of osmoregulated periplasmic glucans in the phytopathogenic bacterium Dickeya dadantii.

PubMed

Bontemps-Gallo, Sébastien; Madec, Edwige; Lacroix, Jean-Marie

2014-04-01

Dickeya dadantii is a phytopathogenic enterobacterium that causes soft rot disease in a wide range of plant species. Maceration, an apparent symptom of the disease, is the result of the synthesis and secretion of a set of plant cell wall-degrading enzymes (PCWDEs), but many additional factors are required for full virulence. Among these, osmoregulated periplasmic glucans (OPGs) and the PecS transcriptional regulator are essential virulence factors. Several cellular functions are controlled by both OPGs and PecS. Strains devoid of OPGs display a pleiotropic phenotype including total loss of virulence, loss of motility and severe reduction in the synthesis of PCWDEs. PecS is one of the major regulators of virulence in D. dadantii, acting mainly as a repressor of various cellular functions including virulence, motility and synthesis of PCWDEs. The present study shows that inactivation of the pecS gene restored virulence in a D. dadantii strain devoid of OPGs, indicating that PecS cannot be de-repressed in strains devoid of OPGs.

Environmental risk assessment of a genetically-engineered microorganism: Erwinia carotovora

DOE Office of Scientific and Technical Information (OSTI.GOV)

Orvos, D.R.

1989-01-01

Environmental use of genetically-engineered microorganisms (GEMs) has raised concerns over potential ecological impact. Development of microcosm systems useful in preliminary testing for risk assessment will provide useful information for predicting potential structural, functional, and genetic effects of GEM release. This study was executed to develop techniques that may be useful in risk assessment and microbial ecology, to ascertain which parameters are useful in determining risk and to predict risk from releasing an engineered strain of Erwinia carotovora. A terrestrial microcosm system for use in GEM risk assessment studies was developed for use in assessing alterations of microbial structure and functionmore » that may be caused by introducing the engineered strain of E. carotovora. This strain is being developed for use as a biological control agent for plant soft rot. Parameters that were monitored included survival and intraspecific competition of E. carotovora, structural effects upon both total bacterial populations and numbers of selected bacterial genera, effects upon activities of dehydrogenase and alkaline phosphatase, effects upon soil nutrients, and potential for gene transfer into or out of the engineered strain.« less

Potato plants genetically modified to produce N-acylhomoserine lactones increase susceptibility to soft rot erwiniae.

PubMed

Toth, I K; Newton, J A; Hyman, L J; Lees, A K; Daykin, M; Ortori, C; Williams, P; Fray, R G

2004-08-01

Many gram-negative bacteria employ N-acylhomoserine lactones (AHL) to regulate diverse physiological processes in concert with cell population density (quorum sensing [QS]). In the plant pathogen Erwinia carotovora, the AHL synthesized via the carI/expI genes are responsible for regulating the production of secreted plant cell wall-degrading exoenzymes and the antibiotic carbapen-3-em carboxylic acid. We have previously shown that targeting the product of an AHL synthase gene (yenI) from Yersinia enterocolitica to the chloroplasts of transgenic tobacco plants caused the synthesis in planta of the cognate AHL signaling molecules N-(3-oxohexanoyl)-L-homoserine lactone (3-oxo-C6-HSL) and N-hexanoylhomoserine lactone (C6-HSL), which in turn, were able to complement a carI-QS mutant. In the present study, we demonstrate that transgenic potato plants containing the yenI gene are also able to express AHL and that the presence and level of these AHL in the plant increases susceptibility to infection by E. carotovora. Susceptibility is further affected by both the bacterial level and the plant tissue under investigation.

Genomic characteristics of vB_PpaP_PP74, a T7-like Autographivirinae bacteriophage infecting a potato pathogen of the newly proposed species Pectobacterium parmentieri.

PubMed

Kabanova, Anastasia; Shneider, Mikhail; Bugaeva, Eugenia; Ha, Vo Thi Ngoc; Miroshnikov, Kirill; Korzhenkov, Aleksei; Kulikov, Eugene; Toschakov, Stepan; Ignatov, Alexander; Miroshnikov, Konstantin

2018-06-01

Bacteriophage vB_PpaP_PP74 (PP74) is a novel virulent phage that infects members of the species Pectobacterium parmentieri, a newly established species of soft-rot-causing bacteria in the family Pectobacteriaceae, derived from potato-specific Pectobacterium wasabiae. vB_PpaP_PP74 was identified as a member of the family Podoviridae by transmission electron microscopy. The phage has a 39,790-bp dsDNA genome containing 50 open reading frames (ORFs). Because of the absence of genes encoding toxins or lysogeny factors, PP74 may be considered a candidate phage for pathogen biocontrol applications. The genome layout is similar to genomes of T7-like phages within the subfamily Autographivirinae, and therefore, functions can be attributed to most of ORFs. However, the closest nucleotide sequence homologs of phage PP74 are unclassified Escherichia phages. Based on phylogenetic analysis, vB_PpaP_PP74 is a sensu lato T7-like phage, but it forms a distant subgenus group together with homologous enterobacterial phages.

Breeding maize for resistance to ear rot caused by Fusarium moniliforme.

PubMed

Hefny, M; Attaa, S; Bayoumi, T; Ammar, S; El-Bramawy, M

2012-01-15

Maize ear rots are among the most important impediments to increased maize production in Egypt. The present research was conducted to estimate combining abilities, heterosis and correlation coefficients for resistance to ear rot disease in seven corn inbred lines and their 21 crosses under field conditions. Results demonstrated that both additive and non-additive gene actions were responsible for the genetic expression of all characters with the preponderance of non-additive actions for days to 50% silking. The parental line L51 was the best combiner for earliness, low infection severity %, high phenols content, short plants and reasonable grain yield, while L101 was good combiner for low ear rot infection only. The cross: L122 x L84, L122 x L101, L51 x L101, L76 x L36, L76 x L84, L36 x L84, L36 x L81 and L36 x L101 which involved one or both parents with good General Combining Ability (GCA) effects expressed useful significant heterosis and Specific Combining Ability (SCA) effects for low infection severity %, high phenol contents, early silking, tall plants and high grain yield. Phenotypic and genotypic correlation coefficients suggest that selection for resistance to ear rot should identify lines with high yielding ability, early silking, tall plants, high phenols content and chitinase activity.

Evaluating an Arachis hypogaea x Arachis diogoi interspecific hybrid derived population for multiple disease resistance

USDA-ARS?s Scientific Manuscript database

The peanut (Arachis hypogaea L.) crop in North Carolina is subject to yield and quality loss from a number of diseases including Cylindrocladium black rot (CBR) caused by Cylindrocladium parasiticum, early leaf spot (ELS) caused by Cercospora arachidicola, late leaf spot (LLS) caused by Cercosporidi...

Stimulation by Erwinia carotovora of the synthesis of ethylene in cauliflower tissue

PubMed Central

Lund, Barbara M.; Mapson, L. W.

1970-01-01

The synthesis of ethylene by cauliflower floret tissue was increased when the tissue was inoculated with the soft-rot bacterium Erwinia carotovora. This effect was clearly associated with the production of pectic enzymes by the micro-organism. These enzymes, acting together with the plant enzymes, stimulated the production of ethylene from methionine. The increased synthetic activity was due to the release and increased activity of a glucose oxidase enzyme apparently attached to plant cell-wall material and liberated by the action of pectic enzymes of the bacterium. ImagesPLATE 1 PMID:5488914

7 CFR 29.6021 - Injury.

Code of Federal Regulations, 2010 CFR

2010-01-01

... may be caused by field diseases, insects, or weather conditions; insecticides, fungicides, or cell... Rule 16), sunburned, sun-scalded, bulk-burnt, pole-burnt, shed-burnt, pole-sweated, stem-rotted...

7 CFR 29.6021 - Injury.

Code of Federal Regulations, 2013 CFR

2013-01-01

... may be caused by field diseases, insects, or weather conditions; insecticides, fungicides, or cell... Rule 16), sunburned, sun-scalded, bulk-burnt, pole-burnt, shed-burnt, pole-sweated, stem-rotted...

7 CFR 29.6021 - Injury.

Code of Federal Regulations, 2012 CFR

2012-01-01

... may be caused by field diseases, insects, or weather conditions; insecticides, fungicides, or cell... Rule 16), sunburned, sun-scalded, bulk-burnt, pole-burnt, shed-burnt, pole-sweated, stem-rotted...

7 CFR 29.6021 - Injury.

Code of Federal Regulations, 2011 CFR

2011-01-01

... may be caused by field diseases, insects, or weather conditions; insecticides, fungicides, or cell... Rule 16), sunburned, sun-scalded, bulk-burnt, pole-burnt, shed-burnt, pole-sweated, stem-rotted...

7 CFR 29.6021 - Injury.

Code of Federal Regulations, 2014 CFR

2014-01-01

... may be caused by field diseases, insects, or weather conditions; insecticides, fungicides, or cell... Rule 16), sunburned, sun-scalded, bulk-burnt, pole-burnt, shed-burnt, pole-sweated, stem-rotted...

Fumonisin B(1)-nonproducing strains of Fusarium verticillioides cause maize (Zea mays) ear infection and ear rot.

PubMed

Desjardins, A E; Plattner, R D

2000-11-01

Fumonisins are polyketide mycotoxins produced by Fusarium verticillioides (synonym F. moniliforme), a major pathogen of maize (Zea mays) worldwide. Most field strains produce high levels of fumonisin B(1) (FB(1)) and low levels of the less-oxygenated homologues FB(2) and FB(3), but fumonisin B(1)-nonproducing field strains have been obtained by natural variation. To test the role of various fumonisins in pathogenesis on maize under field conditions, one strain producing FB(1), FB(2), and FB(3), one strain producing only FB(2), one strain producing only FB(3), and one fumonisin-nonproducing strain were applied to ears via the silk channel and on seeds at planting. Disease severity on the harvested ears was evaluated by visible symptoms and by weight percent symptomatic kernels. Fumonisin levels in kernels were determined by high-performance liquid chromatography. The presence of the applied FB(1)-nonproducing strains in kernels was determined by analysis of recovered strains for fumonisin production and other traits. All three FB(1)-nonproducing strains were able to infect ears following either silk-channel application or seed application at planting and were as effective as the FB(1)-producing strain in causing ear rot following silk-channel application. These results indicate that production of FB(1), FB(2), or FB(3) is not required for F. verticillioides to cause maize ear infection and ear rot.

Positive Regulation of Staphylococcal Enterotoxin H by Rot (Repressor of Toxin) Protein and Its Importance in Clonal Complex 81 Subtype 1 Lineage-Related Food Poisoning

PubMed Central

Sato'o, Yusuke; Hisatsune, Junzo; Nagasako, Yuria; Ono, Hisaya K.; Omoe, Katsuhiko

2015-01-01

We previously demonstrated the clonal complex 81 (CC81) subtype 1 lineage is the major staphylococcal food poisoning (SFP)-associated lineage in Japan (Y. Sato'o et al., J Clin Microbiol 52:2637–2640, 2014, http://dx.doi.org/10.1128/JCM.00661-14). Strains of this lineage produce staphylococcal enterotoxin H (SEH) in addition to SEA. However, an evaluation of the risk for the recently reported SEH has not been sufficiently conducted. We first searched for staphylococcal enterotoxin (SE) genes and SE proteins in milk samples that caused a large SFP outbreak in Japan. Only SEA and SEH were detected, while there were several SE genes detected in the samples. We next designed an experimental model using a meat product to assess the productivity of SEs and found that only SEA and SEH were detectably produced in situ. Therefore, we investigated the regulation of SEH production using a CC81 subtype 1 isolate. Through mutant analysis of global regulators, we found the repressor of toxin (Rot) functioned oppositely as a stimulator of SEH production. SEA production was not affected by Rot. seh mRNA expression correlated with rot both in media and on the meat product, and the Rot protein was shown to directly bind to the seh promoter. The seh promoter sequence was predicted to form a loop structure and to hide the RNA polymerase binding sequences. We propose Rot binds to the promoter sequence of seh and unfolds the secondary structure that may lead the RNA polymerase to bind the promoter, and then seh mRNA transcription begins. This alternative Rot regulation for SEH may contribute to sufficient toxin production by the CC81 subtype 1 lineage in foods to induce SFP. PMID:26341202

Positive Regulation of Staphylococcal Enterotoxin H by Rot (Repressor of Toxin) Protein and Its Importance in Clonal Complex 81 Subtype 1 Lineage-Related Food Poisoning.

PubMed

Sato'o, Yusuke; Hisatsune, Junzo; Nagasako, Yuria; Ono, Hisaya K; Omoe, Katsuhiko; Sugai, Motoyuki

2015-11-01

We previously demonstrated the clonal complex 81 (CC81) subtype 1 lineage is the major staphylococcal food poisoning (SFP)-associated lineage in Japan (Y. Sato'o et al., J Clin Microbiol 52:2637-2640, 2014, http://dx.doi.org/10.1128/JCM.00661-14). Strains of this lineage produce staphylococcal enterotoxin H (SEH) in addition to SEA. However, an evaluation of the risk for the recently reported SEH has not been sufficiently conducted. We first searched for staphylococcal enterotoxin (SE) genes and SE proteins in milk samples that caused a large SFP outbreak in Japan. Only SEA and SEH were detected, while there were several SE genes detected in the samples. We next designed an experimental model using a meat product to assess the productivity of SEs and found that only SEA and SEH were detectably produced in situ. Therefore, we investigated the regulation of SEH production using a CC81 subtype 1 isolate. Through mutant analysis of global regulators, we found the repressor of toxin (Rot) functioned oppositely as a stimulator of SEH production. SEA production was not affected by Rot. seh mRNA expression correlated with rot both in media and on the meat product, and the Rot protein was shown to directly bind to the seh promoter. The seh promoter sequence was predicted to form a loop structure and to hide the RNA polymerase binding sequences. We propose Rot binds to the promoter sequence of seh and unfolds the secondary structure that may lead the RNA polymerase to bind the promoter, and then seh mRNA transcription begins. This alternative Rot regulation for SEH may contribute to sufficient toxin production by the CC81 subtype 1 lineage in foods to induce SFP. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Blastomycosis

MedlinePlus

... dermatitidis fungus. The fungus is found in decaying wood and soil. Causes You can get blastomycosis by ... moist soil, most commonly where there is rotting wood and leaves. The fungus enters the body through ...

Impact of Bacillus cereus NRKT on grape ripe rot disease through resveratrol synthesis in berry skin.

PubMed

Aoki, Takanori; Aoki, Yoshinao; Ishiai, Shiho; Otoguro, Misa; Suzuki, Shunji

2017-01-01

Vine growers are faced with the difficult problem of how to control grape ripe rot disease in vineyards because of fear of accumulation of pesticide residues on grape berries near harvest. Biological control is an alternative non-hazardous technique to control the diseases. Application of resveratrol-synthesis-promoting bacterium, Bacillus cereus strain NRKT, reduced the incidence of grape ripe rot disease caused by Colletotrichum gloeosporioides in a vineyard. The application of NRKT to berry bunches upregulated the gene expression of stilbene synthase, a key enzyme for resveratrol synthesis in berry skins, thereby promoting resveratrol synthesis in berry skins. The potential use of NRKT in vineyards is expected to contribute to the increase in resveratrol content in berry skins, thereby protecting grape berries against fungal diseases. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Pseudomonas cichorii as the causal agent of midrib rot, an emerging disease of greenhouse-grown butterhead lettuce in Flanders.

PubMed

Cottyn, Bart; Heylen, Kim; Heyrman, Jeroen; Vanhouteghem, Katrien; Pauwelyn, Ellen; Bleyaert, Peter; Van Vaerenbergh, Johan; Höfte, Monica; De Vos, Paul; Maes, Martine

2009-05-01

Bacterial midrib rot of greenhouse-grown butterhead lettuce (Lactuca sativa L. var. capitata) is an emerging disease in Flanders (Belgium) and fluorescent pseudomonads are suspected to play an important role in the disease. Isolations from infected lettuces, collected from 14 commercial greenhouses in Flanders, yielded 149 isolates that were characterized polyphasically, which included morphological characteristics, pigmentation, pathogenicity tests by both injection and spraying of lettuce, LOPAT characteristics, FAME analysis, BOX-PCR fingerprinting, 16S rRNA and rpoB gene sequencing, as well as DNA-DNA hybridization. Ninety-eight isolates (66%) exhibited a fluorescent pigmentation and were associated with the genus Pseudomonas. Fifty-five of them induced an HR+ (hypersensitive reaction in tobacco leaves) response. The other 43 fluorescent isolates were most probably saprophytic bacteria and about half of them were able to cause rot on potato tuber slices. BOX-PCR genomic fingerprinting was used to assess the genetic diversity of the Pseudomonas midrib rot isolates. The delineated BOX-PCR patterns matched quite well with Pseudomonas morphotypes defined on the basis of colony appearance and variation in fluorescent pigmentation. 16S rRNA and rpoB gene sequence analyses allowed most of the fluorescent isolates to be allocated to Pseudomonas, and they belonged to either the Pseudomonas fluorescens group, Pseudomonas putida group, or the Pseudomonas cichorii/syringae group. In particular, the isolates allocated to this latter group constituted the vast majority of HR+ isolates and were identified as P. cichorii by DNA-DNA hybridization. They were demonstrated by spray-inoculation tests on greenhouse-grown lettuce to induce the midrib rot disease and could be re-isolated from lesions of inoculated plants. Four HR+ non-fluorescent isolates associated with one sample that showed an atypical midrib rot were identified as Dickeya sp.

Research on basal stem rot (BSR) of ornamental palms caused by basidiospores from Ganoderma boninense.

PubMed

Lim, H P; Fong, Y K

2005-01-01

Basidiospores were isolated from the fruiting bodies of Ganoderma infecting oil palms from an estate in Johor and from ornamental palms (including oil palms) from Singapore. The spores were then germinated to obtain homokaryotic mycelia. Based on clamp connection formation in paired hyphal fusions, tester strains were identified from the homokaryons isolated. Compatibility tests were then carried out using these testers to determine the relatedness of the homokaryotic Ganoderma isolates, both from Johor and from Singapore. Results from the compatibility tests showed that Ganoderma from both locations belong to the same species, while the Ganoderma isolates from Singapore share some common alleles. The pathogenicity tests carried out on Chrysalidocarpus lutescens seedlings using inoculum growing on rubber wood blocks showed that dikaryotic mycelia can cause basal stem rot infection.

Diversity of the Fusarium complex on French maize

USDA-ARS?s Scientific Manuscript database

Ear rot caused by Fusarium species is a major threat to maize production worldwide, causing yield reduction and poor grain quality. In addition, various species of the genus Fusarium can produce mycotoxins, which accumulate in the grain. The distribution and predominance of the different Fusarium sp...

Interaction of Pratylenchus penetrans and Rhizoctonia fragariae in Strawberry Black Root Rot

PubMed Central

LaMondia, J. A.

2003-01-01

A split-root technique was used to examine the interaction between Pratylenchus penetrans and the cortical root-rotting pathogen Rhizoctonia fragariae in strawberry black root rot. Plants inoculated with both pathogens on the same half of a split-root crown had greater levels of root rot than plants inoculated separately or with either pathogen alone. Isolation of R. fragariae from field-grown roots differed with root type and time of sampling. Fungal infection of structural roots was low until fruiting, whereas perennial root colonization was high. Isolation of R. fragariae from feeder roots was variable, but was greater from feeder roots on perennial than from structural roots. Isolation of the fungus was greater from structural roots with nematode lesions than from non-symptomatic roots. Rhizoctonia fragariae was a common resident on the sloughed cortex of healthy perennial roots. From this source, the fungus may infect additional roots. The direct effects of lesion nematode feeding and movement are cortical cell damage and death. Indirect effects include discoloration of the endodermis and early polyderm formation. Perhaps weakened or dying cells caused directly or indirectly by P. penetrans are more susceptible to R. fragariae, leading to increased disease. PMID:19265969

Apple anthracnose canker life cycle and disease cycle

USDA-ARS?s Scientific Manuscript database

Apple anthracnose [caused by Neofabraea malicorticis (H.S. Jacks) anamorph Cryptosporiopsis curvispora (Peck)] is a fungal disease that impacts apple production. The pathogen produces cankers on trees as well as a rot on the fruit known as ‘Bull’s-eye rot’. The cankers cause severe damage to trees...

Characterization of stuA mutants in the mycotoxigenic maize pathogen Fusarium verticillioides

USDA-ARS?s Scientific Manuscript database

Fusarium verticillioides is a major pathogen of maize, causing root, stalk and ear rots and seedling blight. It also produces fumonisin mycotoxins. Ingestion of fumonisin-contaminated corn causes acute toxicity in livestock and is a potential carcinogen to humans. StuA, an APSES protein class transc...

Pre-emergence Damping Off of Beta vulgaris by Rhizopus stolonifer

USDA-ARS?s Scientific Manuscript database

Rhizopus stolonifer (Rs), a cool temperature zygomycete that can cause a post-harvest rot on sugarbeet (Beta vulgaris), also causes pre-emergence damping off in other crops. We are interested in its potential pre-emergence damping off activity in sugarbeet. Sugarbeets are quite susceptible to seedli...

Conjunctively screening of biocontrol agents (BCAs) against fusarium root rot and fusarium head blight caused by Fusarium graminearum.

PubMed

Wang, Lu-Yao; Xie, Yue-Shen; Cui, Yuan-Yu; Xu, Jianjun; He, Wei; Chen, Huai-Gu; Guo, Jian-Hua

2015-08-01

Fusarium root-rot and fusarium head blight are plant diseases caused by Fusarium sp. in different growth periods of wheat, bring heavy losses to crop production in China. This research is aiming to screen biocontrol agents conjunctively for controlling these two diseases at the same time, as well as evaluate our previous BCAs (Biological Control Agents) screening strategies in more complex situation, considering biocontrol is well concerned as an environmental-friendly plant disease controlling method. Totally 966 bacterial isolates were screened from different parts of wheat tissues, of which potential biocontrol values were detected according to their abilities in antagonism inhibition and secreting extracellular hydrolytic enzyme. Biocontrol tests against fusarium root rot and fusarium head blight were carried out on 37 bacterial isolates with potential biocontrol capacity after pre-selection through ARDRA- and BOX-PCR analysis on strains with high assessment points. We acquired 10 BCAs with obvious biocontrol efficacy (more than 40%) in greenhouse and field tests. Pseudomonas fluorescens LY1-8 performed well in both two tests (biocontrol efficacy: 44.62% and 58.31%), respectively. Overall, correlation coefficient is 0.720 between assessment values of 37 tested BCA strains and their biocontrol efficacy in trails against fusarium root rot; correlation coefficient is 0.806 between their assessment values and biocontrol efficacy in trails against fusarium head blight. We acquired 10 well-performed potential BCAs, especially P. fluorescens LY1-8 displayed good biocontrol capacity against two different diseases on wheat. Biocontrol efficacies results in both greenhouse and field tests showed high positive correlation with assessment values (0.720 and 0.806), suggesting that the BCAs screening and assessing strategy previously developed in our lab is also adaptable for conjunctively screening BCAs for controlling both root and shoot diseases on wheat caused by same fungal pathogen. Copyright © 2015 Elsevier GmbH. All rights reserved.

Potential of Wood-Rotting Fungi to Attack Polystyrene Sulfonate and Its Depolymerisation by Gloeophyllum trabeum via Hydroquinone-Driven Fenton Chemistry

PubMed Central

Krueger, Martin C.; Hofmann, Ulrike; Moeder, Monika; Schlosser, Dietmar

2015-01-01

Synthetic polymers often pose environmental hazards due to low biodegradation rates and resulting accumulation. In this study, a selection of wood-rotting fungi representing different lignocellulose decay types was screened for oxidative biodegradation of the polymer polystyrene sulfonate (PSS). Brown-rot basidiomycetes showed PSS depolymerisation of up to 50 % reduction in number-average molecular mass (Mn) within 20 days. In-depth investigations with the most efficient depolymeriser, a Gloeophyllum trabeum strain, pointed at extracellular hydroquinone-driven Fenton chemistry responsible for depolymerisation. Detection of hydroxyl radicals present in the culture supernatants showed good compliance with depolymerisation over the time course of PSS degradation. 2,5-Dimethoxy-1,4-hydroquinone (2,5-DMHQ), which was detected in supernatants of active cultures via liquid chromatography and mass spectrometry, was demonstrated to drive the Fenton processes in G. trabeum cultures. Up to 80% reduction in Mn of PSS where observed when fungal cultures were additionally supplemented with 2,5-dimethoxy benzoquinone, the oxidized from of 2,5-DMHQ. Furthermore, 2,5-DMHQ could initiate the Fenton's reagent-mediated PSS depolymerisation in cell-free systems. In contrast, white-rot fungi were unable to cause substantial depolymerising effects despite the expression of lignin-modifying exo-enzymes. Detailed investigations with laccase from Trametes versicolor revealed that only in presence of certain redox mediators limited PSS depolymerisation occurred. Our results indicate that brown-rot fungi might be suitable organisms for the biodegradation of recalcitrant synthetic polymeric pollutants. PMID:26147966

Genome-wide SNP identification and QTL mapping for black rot resistance in cabbage.

PubMed

Lee, Jonghoon; Izzah, Nur Kholilatul; Jayakodi, Murukarthick; Perumal, Sampath; Joh, Ho Jun; Lee, Hyeon Ju; Lee, Sang-Choon; Park, Jee Young; Yang, Ki-Woung; Nou, Il-Sup; Seo, Joodeok; Yoo, Jaeheung; Suh, Youngdeok; Ahn, Kyounggu; Lee, Ji Hyun; Choi, Gyung Ja; Yu, Yeisoo; Kim, Heebal; Yang, Tae-Jin

2015-02-03

Black rot is a destructive bacterial disease causing large yield and quality losses in Brassica oleracea. To detect quantitative trait loci (QTL) for black rot resistance, we performed whole-genome resequencing of two cabbage parental lines and genome-wide SNP identification using the recently published B. oleracea genome sequences as reference. Approximately 11.5 Gb of sequencing data was produced from each parental line. Reference genome-guided mapping and SNP calling revealed 674,521 SNPs between the two cabbage lines, with an average of one SNP per 662.5 bp. Among 167 dCAPS markers derived from candidate SNPs, 117 (70.1%) were validated as bona fide SNPs showing polymorphism between the parental lines. We then improved the resolution of a previous genetic map by adding 103 markers including 87 SNP-based dCAPS markers. The new map composed of 368 markers and covers 1467.3 cM with an average interval of 3.88 cM between adjacent markers. We evaluated black rot resistance in the mapping population in three independent inoculation tests using F2:3 progenies and identified one major QTL and three minor QTLs. We report successful utilization of whole-genome resequencing for large-scale SNP identification and development of molecular markers for genetic map construction. In addition, we identified novel QTLs for black rot resistance. The high-density genetic map will promote QTL analysis for other important agricultural traits and marker-assisted breeding of B. oleracea.

Computing the Rotational Diffusion of Biomolecules via Molecular Dynamics Simulation and Quaternion Orientations.

PubMed

Chen, Po-Chia; Hologne, Maggy; Walker, Olivier

2017-03-02

Rotational diffusion (D rot ) is a fundamental property of biomolecules that contains information about molecular dimensions and solute-solvent interactions. While ab initio D rot prediction can be achieved by explicit all-atom molecular dynamics simulations, this is hindered by both computational expense and limitations in water models. We propose coarse-grained force fields as a complementary solution, and show that the MARTINI force field with elastic networks is sufficient to compute D rot in >10 proteins spanning 5-157 kDa. We also adopt a quaternion-based approach that computes D rot orientation directly from autocorrelations of best-fit rotations as used in, e.g., RMSD algorithms. Over 2 μs trajectories, isotropic MARTINI+EN tumbling replicates experimental values to within 10-20%, with convergence analyses suggesting a minimum sampling of >50 × τ theor to achieve sufficient precision. Transient fluctuations in anisotropic tumbling cause decreased precision in predictions of axisymmetric anisotropy and rhombicity, the latter of which cannot be precisely evaluated within 2000 × τ theor for GB3. Thus, we encourage reporting of axial decompositions D x , D y , D z to ease comparability between experiment and simulation. Where protein disorder is absent, we observe close replication of MARTINI+EN D rot orientations versus CHARMM22*/TIP3p and experimental data. This work anticipates the ab initio prediction of NMR-relaxation by combining coarse-grained global motions with all-atom local motions.

Growth Promoting Rhizospheric and Endophytic Bacteria from Curcuma longa L. as Biocontrol Agents against Rhizome Rot and Leaf Blight Diseases.

PubMed

Vinayarani, G; Prakash, H S

2018-06-01

Plant growth promoting rhizobacteria and endophytic bacteria were isolated from different varieties of turmeric ( Curcuma longa L.) from South India. Totally 50 strains representing, 30 PGPR and 20 endophytic bacteria were identified based on biochemical assays and 16S rDNA sequence analysis. The isolates were screened for antagonistic activity against Pythium aphanidermatum (Edson) Fitzp., and Rhizoctonia solani Kuhn., causing rhizome rot and leaf blight diseases in turmeric, by dual culture and liquid culture assays. Results revealed that only five isolates of PGPR and four endophytic bacteria showed more than 70% suppression of test pathogens in both assays. The SEM studies of interaction zone showed significant ultrastructural changes of the hyphae like shriveling, breakage and desication of the pathogens by PGPR B. cereus (RBac-DOB-S24) and endophyte P. aeruginosa (BacDOB-E19). Selected isolates showed multiple Plant growth promoting traits. The rhizome bacterization followed by soil application of B. cereus (RBacDOB-S24) showed lowest Percent Disease Incidence (PDI) of rhizome rot and leaf blight, 16.4% and 15.5% respectively. Similarly, P. aeruginosa (BacDOB-E19) recorded PDI of rhizome rot (17.5%) and leaf blight (17.7%). The treatment of these promising isolates exhibited significant increase in plant height and fresh rhizome yield/plant in comparison with untreated control under greenhouse condition. Thereby, these isolates can be exploited as a potential biocontrol agent for suppressing rhizome rot and leaf blight diseases in turmeric.

Draft genome resources for the phytopathogenic fungi Monilinia fructicola, M. fructigena, M. polystroma and M. laxa, the causal agents of brown rot.

PubMed

Rivera, Yazmin; Zeller, Kurt; Srivastava, Subodh K; Sutherland, Jeremy; Galvez, Marco E; Nakhla, Mark K; Poniatowska, Anna; Schnabel, Guido; Sundin, George W; Abad, Gloria

2018-05-03

Fungi in the genus Monilinia are known to cause devastating brown rot disease of stone and pome fruits. Here, we report the draft genome assemblies of four important phytopathogenic species: Monilinia fructicola, Monilinia fructigena, Monilinia polystroma, and Monilinia laxa. The draft genome assemblies were 39 Mb (M. fructigena), 42 Mb (M. laxa), 43 Mb (M. fructicola), and 45 Mb (M. polystroma) with as few as 550 contigs (M. laxa). These are the first draft genome resources publicly available for M. laxa, M. fructigena, and M. polystroma.

Draft whole genome sequence of groundnut stem rot fungus Athelia rolfsii revealing genetic architect of its pathogenicity and virulence.

PubMed

Iquebal, M A; Tomar, Rukam S; Parakhia, M V; Singla, Deepak; Jaiswal, Sarika; Rathod, V M; Padhiyar, S M; Kumar, Neeraj; Rai, Anil; Kumar, Dinesh

2017-07-13

Groundnut (Arachis hypogaea L.) is an important oil seed crop having major biotic constraint in production due to stem rot disease caused by fungus, Athelia rolfsii causing 25-80% loss in productivity. As chemical and biological combating strategies of this fungus are not very effective, thus genome sequencing can reveal virulence and pathogenicity related genes for better understanding of the host-parasite interaction. We report draft assembly of Athelia rolfsii genome of ~73 Mb having 8919 contigs. Annotation analysis revealed 16830 genes which are involved in fungicide resistance, virulence and pathogenicity along with putative effector and lethal genes. Secretome analysis revealed CAZY genes representing 1085 enzymatic genes, glycoside hydrolases, carbohydrate esterases, carbohydrate-binding modules, auxillary activities, glycosyl transferases and polysaccharide lyases. Repeat analysis revealed 11171 SSRs, LTR, GYPSY and COPIA elements. Comparative analysis with other existing ascomycotina genome predicted conserved domain family of WD40, CYP450, Pkinase and ABC transporter revealing insight of evolution of pathogenicity and virulence. This study would help in understanding pathogenicity and virulence at molecular level and development of new combating strategies. Such approach is imperative in endeavour of genome based solution in stem rot disease management leading to better productivity of groundnut crop in tropical region of world.

Potential of UVC germicidal irradiation in suppressing crown rot disease, retaining postharvest quality and antioxidant capacity of Musa AAA "Berangan" during fruit ripening.

PubMed

S Mohamed, Nuratika Tamimi; Ding, Phebe; Kadir, Jugah; M Ghazali, Hasanah

2017-09-01

Crown rot caused by fungal pathogen is the most prevalent postharvest disease in banana fruit that results significant economic losses during transportation, storage, and ripening period. Antifungal effects of ultraviolet C (UVC) irradiation at doses varied from 0.01 to 0.30 kJ m -2 were investigated in controlling postharvest crown rot disease, maintenance of fruit quality, and the effects on antioxidant capacity of Berangan banana fruit during ripening days at 25 ± 2°C and 85% RH. Fruits irradiated with 0.30 kJ m -2 exhibited the highest (i.e., 62.51%) reduction in disease severity. However, the application of UVC at all doses caused significant browning damages on fruit peel except the dose of 0.01 kJ m -2 . This dose synergistically reduced 46.25% development of postharvest crown and did not give adverse effects on respiration rate, ethylene production, weight loss, firmness, color changes, soluble solids concentration, titratable acidity, and pH in banana as compared to the other treatments and control. Meanwhile, the dose also enhanced a significant higher level of total phenolic content, FRAP, and DPPH values than in control fruits indicating the beneficial impact of UVC in fruit nutritional quality. The results of scanning electron micrographs confirmed that UVC irradiation retarded the losses of wall compartments, thereby maintained the cell wall integrity in the crown tissue of banana fruit. The results suggest that using 0.01 kJ m -2 UVC irradiation dose as postharvest physical treatment, the crown rot disease has potential to be controlled effectively together with maintaining quality and antioxidant of banana fruit.

Identification and Differentiation of Monilinia Species Causing Brown Rot of Pome and Stone Fruit using High-Resolution Melting (HRM) Analysis.

PubMed

Papavasileiou, Antonios; Madesis, Panagiotis B; Karaoglanidis, George S

2016-09-01

Brown rot is a devastating disease of stone fruit caused by Monilinia spp. Among these species, Monilinia fructicola is a quarantine pathogen in Europe but has recently been detected in several European countries. Identification of brown rot agents relies on morphological differences or use of molecular methods requiring fungal isolation. The current study was initiated to develop and validate a high-resolution melting (HRM) method for the identification of the Monilinia spp. and for the detection of M. fructicola among other brown rot pathogens. Based on the sequence of the cytb intron from M. laxa, M. fructicola, M. fructigena, M. mumecola, M. linhartiana, and M. yunnanensis isolates originating from several countries, a pair of universal primers for species identification and a pair of primers specific to M. fructicola were designed. The specificity of the primers was verified to ensure against cross-reaction with other fungal species. The melting curve analysis using the universal primers generated six different HRM curve profiles, each one specific for each species. Τhe HRM analysis primers specific to M. fructicola amplified a 120-bp region with a distinct melt profile corresponding to the presence of M. fructicola, regardless of the presence of other species. HRM analysis can be a useful tool for rapid identification and differentiation of the six Monilinia spp. using a single primer pair. This novel assay has the potential for simultaneous identification and differentiation of the closely related Monilinia spp. as well as for the differentiation of M. fructicola from other common pathogens or saprophytes that may occur on the diseased fruit.

FUM and BIK gene expression contribute to describe fumonisin and bikaverin synthesis in Fusarium verticillioides

USDA-ARS?s Scientific Manuscript database

Fusarium verticillioides is a maize-pathogen that causes ear and stalk rot and produces toxic secondary metabolites including fumonisins and bikaverin. Fumonisins are known to cause disease in animals and humans; bikaverin is a pigment associated with self-defense. Water activity (aw) is one of the ...

Postharvest respiration rate and sucrose concentration of Rhizoctonia-infected sugar beet roots

USDA-ARS?s Scientific Manuscript database

Rhizoctonia crown and root rot (RCRR), caused by Rhizoctonia solani AG 2-2, is a common root disease on sugar beet that reduces yield and sucrose during the growing season and causes further losses by increasing respiration and reducing sucrose content during storage. The industry needs to identify...

Candida sake CPA-1 and other biologically based products as potential control strategies to reduce sour rot of grapes.

PubMed

Calvo-Garrido, C; Viñas, I; Elmer, P; Usall, J; Teixidó, N

2013-10-01

Sour rot of grapes is becoming increasingly important disease in many wine-growing regions, while consistent chemical or biological control has not been reported. Authors evaluated relative incidence and severity of sour rot in untreated grapevines and the effect of different biologically based treatments on sour rot at harvest. Applications of Candida sake CPA-1 plus Fungicover® , Ulocladium oudemansii and chitosan were carried out in an organic vineyard in Lleida area, Spain, during the 2009 and 2010 growing seasons. At harvest, incidence and severity of sour rot were assessed. Significantly higher incidence and severity of sour rot were observed in untreated plots in 2009, when meteorological conditions after veraison were warmer. All treatments including C. sake CPA-1 significantly reduced (P < 0·05) severity of sour rot in both seasons, ranging from 40 to 67% compared with the untreated control. Incidence of sour rot was not significantly reduced by any treatment. This study helps to characterize development of sour rot in the dry Mediterranean climate conditions of the experiment, whereas also represents the first report of biological control of sour rot. Treatments with the tested biologically based products are a promising strategy to control sour rot. Studies on sour rot of grapes are scarce in literature, and this is the first work specifically evaluating sour rot in Spanish vineyards. Sour rot control in field conditions through applications of antagonistic micro-organisms is reported for first time in this study, showing elevated severity reductions (40-67% compared with control). As there are no options available for sour rot control in vineyards, results point Candida sake CPA-1 as an interesting control strategy against grape bunch rots. © 2013 The Society for Applied Microbiology.

Preliminary study on antifungal effect of commercial essential oils against white rot fungi

NASA Astrophysics Data System (ADS)

Khalid, Nurul Izzaty; Baharum, Azizah; Daud, Fauzi

2015-09-01

Protecting and preserving wood plastic composite from deterioration caused by fungal attack is a high challenge issue to cater nowadays. The objective of this study was to carry out a screening test towards antifungal effect of essential oil and to investigate the potential of raw materials that will be used as basic material for manufacturing wood plastic composite against white rot fungi. Essential oils from four types of natural products comprising cinnamon, lemongrass, lavender and geranium have been screened for their ability to inhibit five types of white rot fungi species which are Lentinus squarrosulus, Pleuorotus pulmonarius, Lentinus sp., Pleuorotus sajor-caju and Lignosus rhinocerus. The antifungal evaluation showed that no inhibitory effect against tested white rot fungi since the mycelia completely filled the plates. From the observation, mycelia of L. squarrosulus, P. pulmonarius and Lentinus sp. were found to filled the surface of falcon tubes with rubber sawdust after 15 days. Mycelia of L. squarrosulus and P. pulmonarius also were found to completely covered the surface of media that contain polypropylene and maleic anhydride grafted polypropylene on it. Therefore, this report proved that the main materials that will be applicable in manufacturing of wood plastic composite had potential to be degraded by this type of fungal attack.

Combination of antagonistic yeasts with two food additives for control of brown rot caused by Monilinia fructicola on sweet cherry fruit.

PubMed

Qin, G Z; Tian, S P; Xu, Y; Chan, Z L; Li, B Q

2006-03-01

To evaluate beneficial effect of two food additives, ammonium molybdate (NH4-Mo) and sodium bicarbonate (NaBi), on antagonistic yeasts for control of brown rot caused by Monilinia fructicola in sweet cherry fruit under various storage conditions. The mechanisms of action by which food additives enhance the efficacy of antagonistic yeasts were also evaluated. Biocontrol activity of Pichia membranefaciens and Cryptococcus laurentii against brown rot in sweet cherry fruit was improved by addition of 5 mmol l(-1) NH4-Mo or 2% NaBi when stored in air at 20 and 0 degrees C, and in controlled atmosphere (CA) storage with 10% O2 + 10% CO2 at 0 degrees C. Population dynamics of P. membranefaciens in the wounds of fruit were inhibited by NH4-Mo at 20 degrees C after 1 day of incubation and growth of C. laurentii was inhibited by NH4-Mo at 0 degrees C in CA storage after 60 days. In contrast, NaBi did not significantly influence growth of the two yeasts in fruit wounds under various storage conditions except that the growth of P. membranefaciens was stimulated after storage for 45 days at 0 degrees C in CA storage. When used alone, the two additives showed effective control of brown rot in sweet cherry fruit and the efficacy was closely correlated with the concentrations used. The result of in vitro indicated that growth of M. fructicola was significantly inhibited by NH4-Mo and NaBi. Application of additives improved biocontrol of brown rot on sweet cherry fruit under various storage conditions. It is postulated that the enhancement of disease control is directly because of the inhibitory effects of additives on pathogen growth, and indirectly because of the relatively little influence of additives on the growth of antagonistic yeasts. The results obtained in this study suggest that an integration of NH4-Mo or NaBi with biocontrol agents has great potential in commercial management of postharvest diseases of fruit.

Identification of the infection route of a Fusarium seed pathogen into nondormant Bromus tectorum seeds

Treesearch

JanaLynn Franke; Brad Geary; Susan E. Meyer

2014-01-01

The genus Fusarium has a wide host range and causes many different forms of plant disease. These include seed rot and seedling blight diseases of cultivated plants. The diseases caused by Fusarium on wild plants are less well-known. In this study, we examined disease development caused by Fusarium sp. n on nondormant seeds of the important rangeland weed Bromus...

Degradation of alkylphenols by white rot fungus Irpex lacteus and its manganese peroxidase.

PubMed

Moon, Dong-Soo; Song, Hong-Gyu

2012-10-01

Alkylphenols are common endocrine disrupters that are produced from the degradation of widely used surfactants. Since they cause various harmful effects on aquatic life and in humans, they should be removed from the environments being contaminated. White rot fungus Irpex lacteus can completely degrade 100 mg/L of octylphenol, nonylphenol, and phenylphenol during 1 day of incubation in the complex YMG medium, which was the highest degrading capability among nine strains of white rot fungi tested. In the N-limited Kirk's basal salts medium, I. lacteus could degrade almost 100 % of 100 mg/L octylphenol and nonylphenol in 1 h, and exhibited a high activity of manganese peroxidase (MnP; 1,790 U/L). MnP of I. lacteus was purified by ion exchange chromatography, and this degraded 99 % of 50 mg/L octylphenol and removed 80 % of estrogenic activity in 2 hours. In addition, the purified MnP (10 U/mL) degraded over 90 % of 50 mg/L nonylphenol in 1 h.

Hardwood Diseases

Treesearch

T. H. Filer

1981-01-01

Damping-off and root-rot continue to cause the most losses of young hardwood seedlings. We know how to control these losses but we gamble by not taking preventative methods. The most effective control is to use soil fumigation or solar soil sterilization.

Epicormic branching on eight species of Appalachian hardwoods

Treesearch

H. Clay Smith

1966-01-01

Epicormic branches and associated defects are leading causes of degrade and value loss in lumber sawed from hardwood logs. The degrade may be in the form of small knots, ingrown bark, wood blemishes, and/or rot.

White mold of Jerusalem artichoke

USDA-ARS?s Scientific Manuscript database

Jerusalem artichoke (Helianthus tuberosus) is a Native American food plant closely related to the common sunflower (Helianthus annuus). Tubers of Jerusalem artichoke are increasingly available in retail grocery outlets. White mold (Sclerotinia stem rot), caused by the fungus, Sclerotinia sclerotioru...

Spatial Heterogeneity of SOM Concentrations Associated with White-rot Versus Brown-rot Wood Decay.

PubMed

Bai, Zhen; Ma, Qiang; Dai, Yucheng; Yuan, Haisheng; Ye, Ji; Yu, Wantai

2017-10-23

White- and brown-rot fungal decay via distinct pathways imparts characteristic molecular imprints on decomposing wood. However, the effect that a specific wood-rotting type of fungus has on proximal soil organic matter (SOM) accumulation remains unexplored. We investigated the potential influence of white- and brown-rot fungi-decayed Abies nephrolepis logs on forest SOM stocks (i.e., soil total carbon (C) and nitrogen (N)) and the concentrations of amino sugars (microbial necromass) at different depths and horizontal distances from decaying woody debris. The brown-rot fungal wood decay resulted in higher concentrations of soil C and N and a greater increase in microbial necromass (i.e., 1.3- to 1.7-fold greater) than the white-rot fungal wood decay. The white-rot sets were accompanied by significant differences in the proportions of the bacterial residue index (muramic acid%) with soil depth; however, the brown-rot-associated soils showed complementary shifts, primarily in fungal necromass, across horizontal distances. Soil C and N concentrations were significantly correlated with fungal rather than bacterial necromass in the brown-rot systems. Our findings confirmed that the brown-rot fungi-dominated degradation of lignocellulosic residues resulted in a greater SOM buildup than the white-rot fungi-dominated degradation.

Extensive sampling of basidiomycete genomes demonstrates inadequacy of the white-rot/brown-rot paradigm for wood decay fungi

PubMed Central

Riley, Robert; Salamov, Asaf A.; Brown, Daren W.; Nagy, Laszlo G.; Floudas, Dimitrios; Held, Benjamin W.; Levasseur, Anthony; Lombard, Vincent; Morin, Emmanuelle; Otillar, Robert; Lindquist, Erika A.; Sun, Hui; LaButti, Kurt M.; Schmutz, Jeremy; Jabbour, Dina; Luo, Hong; Baker, Scott E.; Pisabarro, Antonio G.; Walton, Jonathan D.; Blanchette, Robert A.; Henrissat, Bernard; Martin, Francis; Cullen, Dan; Hibbett, David S.; Grigoriev, Igor V.

2014-01-01

Basidiomycota (basidiomycetes) make up 32% of the described fungi and include most wood-decaying species, as well as pathogens and mutualistic symbionts. Wood-decaying basidiomycetes have typically been classified as either white rot or brown rot, based on the ability (in white rot only) to degrade lignin along with cellulose and hemicellulose. Prior genomic comparisons suggested that the two decay modes can be distinguished based on the presence or absence of ligninolytic class II peroxidases (PODs), as well as the abundance of enzymes acting directly on crystalline cellulose (reduced in brown rot). To assess the generality of the white-rot/brown-rot classification paradigm, we compared the genomes of 33 basidiomycetes, including four newly sequenced wood decayers, and performed phylogenetically informed principal-components analysis (PCA) of a broad range of gene families encoding plant biomass-degrading enzymes. The newly sequenced Botryobasidium botryosum and Jaapia argillacea genomes lack PODs but possess diverse enzymes acting on crystalline cellulose, and they group close to the model white-rot species Phanerochaete chrysosporium in the PCA. Furthermore, laboratory assays showed that both B. botryosum and J. argillacea can degrade all polymeric components of woody plant cell walls, a characteristic of white rot. We also found expansions in reducing polyketide synthase genes specific to the brown-rot fungi. Our results suggest a continuum rather than a dichotomy between the white-rot and brown-rot modes of wood decay. A more nuanced categorization of rot types is needed, based on an improved understanding of the genomics and biochemistry of wood decay. PMID:24958869

Relationship of soil properties and sugarcane yields to red stripe in Louisiana

USDA-ARS?s Scientific Manuscript database

Red stripe of sugarcane caused by Acidovorax avenae subsp. avenae consists of two forms: leaf stripe and top rot. Symptoms of red stripe in Louisiana observed by the authors between 1985 and 2010 were limited to the leaf stripe form which caused no apparent yield loss. During 2010, the more severe t...

First report of Monilinia fructicola causing postharvest decay of strawberries (Fragaria ananassa) in the United States

USDA-ARS?s Scientific Manuscript database

Monilinia fructicola is a world-wide economically important pathogen of stone fruits causing brown rot before and after harvest. In early summer of 2016, signs of Monilinia spp. decay were observed on strawberry fruit, harvested from organically grown plants in a high tunnel located in the middle o...

Molecules that inhibit growth of Fusarium graminearum, a pathogen causing disease in wheat and corn

USDA-ARS?s Scientific Manuscript database

Fusarium graminearum can cause head blight in wheat and stalk or ear rot in corn, which results in crop losses. Discovery of novel antifungal resistance proteins are crucial to mitigating crop losses. We found, via in vitro studies, a small cationic peptide was capable of inhibiting the growth of th...

A multiplex PCR assay to detect and differentiate select agent strains of Ralstonia solanacearum

USDA-ARS?s Scientific Manuscript database

Ralstonia solanacearum causes bacterial wilt in a variety of cash crops. R. solanacearum race 3 biovar 2 strains are considered select agents by the U.S. Government because they are not endemic to the U.S. and have the potential to cause brown rot disease in our potato production fields. Simple and...

Response of U.S. Bottle Gourd (Lagenaria siceraria) Plant Introductions (PI) to Crown Rot caused by Phytophthora Capsici

USDA-ARS?s Scientific Manuscript database

Phytophthora capsici can cause severe damage to cucurbit crops grown in open fields in the southeast regions of US. In recent years, there has been a growing interest in the US in grafting watermelon plants onto various cucurbit rootstocks including bottle gourds for managing soil borne diseases. ...

An opportunistic Pantoea sp. isolated from a cotton fleahopper that is capable of causing cotton (Gossypium hirsutum L.) bud rot

USDA-ARS?s Scientific Manuscript database

Pantoea ananatis (Serano) representatives are known to have a broad host range including both humans and plants. The cotton fleahopper (Pseudatomoscelis seriatus, Reuter) is a significant pest that causes cotton bud damage that may result in significant yield losses. In this study, cotton fleahopp...

Influence of water activity on fumonisin and bikaverin gene expression and toxin production in fusarium verticillioides

USDA-ARS?s Scientific Manuscript database

Fusarium verticillioides is known as the main cause of ear rot disease in maize. It can produce a variety of secondary metabolites including fumonisins (FUM) and bikaverin (BIK). The former are toxins known to cause diseases and cancers in both animals and humans; the latter is a red-pigment with de...

Xanthomonas campestris pv. campestris (cause of black rot of crucifers) in the genomic era is still a worldwide threat to brassica crops.

PubMed

Vicente, Joana G; Holub, Eric B

2013-01-01

Xanthomonas campestris pv. campestris (Xcc) (Pammel) Dowson is a Gram-negative bacterium that causes black rot, the most important disease of vegetable brassica crops worldwide. Intensive molecular investigation of Xcc is gaining momentum and several whole genome sequences are available. Bacteria; Phylum Proteobacteria; Class Gammaproteobacteria; Order Xanthomonadales; Family Xanthomonadacea; Genus Xanthomonas; Species X. campestris. Xcc can cause disease in a large number of species of Brassicaceae (ex-Cruciferae), including economically important vegetable Brassica crops and a number of other cruciferous crops, ornamentals and weeds, including the model plant Arabidopsis thaliana. Black rot is a systemic vascular disease. Typical disease symptoms include V-shaped yellow lesions starting from the leaf margins and blackening of the veins. Collections of Xcc isolates have been differentiated into physiological races based on the response of several brassica species lines. Black rot is a seed-borne disease. The disease is favoured by warm, humid conditions and can spread rapidly from rain dispersal and irrigation water. The control of black rot is difficult and relies on the use of pathogen-free planting material and the elimination of other potential inoculum sources (infected crop debris and cruciferous weeds). Major gene resistance is very rare in B. oleracea (brassica C genome). Resistance is more readily available in other species, including potentially useful sources of broad-spectrum resistance in B. rapa and B. carinata (A and BC genomes, respectively) and in the wild relative A. thaliana. The reference genomes of three isolates have been released. The genome consists of a single chromosome of approximately 5 100 000 bp, with a GC content of approximately 65% and an average predicted number of coding DNA sequences (CDS) of 4308. Three different secretion systems have been identified and studied in Xcc. The gene clusters xps and xcs encode a type II secretion system and xps genes have been linked to pathogenicity. The role of the type IV secretion system in pathogenicity is still uncertain. The hrp gene cluster encodes a type III secretion system that is associated with pathogenicity. An inventory of candidate effector genes has been assembled based on homology with known effectors. A range of other genes have been associated with virulence and pathogenicity, including the rpf, gum and wxc genes involved in the regulation of the synthesis of extracellular degrading enzymes, xanthan gum and lipopolysaccharides. http://www.xanthomonas.org/ © 2012 THE AUTHORS. MOLECULAR PLANT PATHOLOGY © 2012 BSPP AND BLACKWELL PUBLISHING LTD.

Root rot in sugar beet piles at harvest

USDA-ARS?s Scientific Manuscript database

Sugar beet root rots are not only a concern because of reduced yields, but can also be associated with losses in storage. Our primary sugar beet root rot disease problem in the Amalgamated production area is Rhizoctonia root rot. However, this rot frequently only penetrates a short distance past t...

Evaluation of stem rot in 339 Bornean tree species: implications of size, taxonomy, and soil-related variation for aboveground biomass estimates

NASA Astrophysics Data System (ADS)

Heineman, K. D.; Russo, S. E.; Baillie, I. C.; Mamit, J. D.; Chai, P. P.-K.; Chai, L.; Hindley, E. W.; Lau, B.-T.; Tan, S.; Ashton, P. S.

2015-10-01

Fungal decay of heart wood creates hollows and areas of reduced wood density within the stems of living trees known as stem rot. Although stem rot is acknowledged as a source of error in forest aboveground biomass (AGB) estimates, there are few data sets available to evaluate the controls over stem rot infection and severity in tropical forests. Using legacy and recent data from 3180 drilled, felled, and cored stems in mixed dipterocarp forests in Sarawak, Malaysian Borneo, we quantified the frequency and severity of stem rot in a total of 339 tree species, and related variation in stem rot with tree size, wood density, taxonomy, and species' soil association, as well as edaphic conditions. Predicted stem rot frequency for a 50 cm tree was 53 % of felled, 39 % of drilled, and 28 % of cored stems, demonstrating differences among methods in rot detection ability. The percent stem volume infected by rot, or stem rot severity, ranged widely among trees with stem rot infection (0.1-82.8 %) and averaged 9 % across all trees felled. Tree taxonomy explained the greatest proportion of variance in both stem rot frequency and severity among the predictors evaluated in our models. Stem rot frequency, but not severity, increased sharply with tree diameter, ranging from 13 % in trees 10-30 cm DBH to 54 % in stems ≥ 50 cm DBH across all data sets. The frequency of stem rot increased significantly in soils with low pH and cation concentrations in topsoil, and stem rot was more common in tree species associated with dystrophic sandy soils than with nutrient-rich clays. When scaled to forest stands, the maximum percent of stem biomass lost to stem rot varied significantly with soil properties, and we estimate that stem rot reduces total forest AGB estimates by up to 7 % relative to what would be predicted assuming all stems are composed strictly of intact wood. This study demonstrates not only that stem rot is likely to be a significant source of error in forest AGB estimation, but also that it strongly covaries with tree size, taxonomy, habitat association, and soil resources, underscoring the need to account for tree community composition and edaphic variation in estimating carbon storage in tropical forests.

21 CFR 520.2260a - Sulfamethazine oblet, tablet, and bolus.

Code of Federal Regulations, 2011 CFR

2011-04-01

... sulfamethazine: bacterial scours (colibacilloosis) caused by E. coli; necrotic pododermatitis (foot rot) and calf... (shipping fever complex) (Pasteurella spp.), colibacillosis (bacterial scours) (Escherichia coli), necrotic... spp.), strangles (Streptococcus equi), and bacterial enteritis (Escherichia coli). (iii) Limitations...

Identification of Pathogenic Fusarium spp. Causing Maize Ear Rot and Potential Mycotoxin Production in China

PubMed Central

Duan, Canxing; Qin, Zihui; Yang, Zhihuan; Li, Weixi; Sun, Suli; Zhu, Zhendong; Wang, Xiaoming

2016-01-01

Ear rot is a serious disease that affects maize yield and grain quality worldwide. The mycotoxins are often hazardous to humans and livestock. In samples collected in China between 2009 and 2014, Fusarium verticillioides and F. graminearum species complex were the dominant fungi causing ear rot. According to the TEF-1α gene sequence, F. graminearum species complex in China included three independent species: F. graminearum, F. meridionale, and F. boothii. The key gene FUM1 responsible for the biosynthesis of fumonisin was detected in all 82 F. verticillioides isolates. Among these, 57 isolates mainly produced fumonisin B1, ranging from 2.52 to 18,416.44 µg/g for each gram of dry hyphal weight, in vitro. Three different toxigenic chemotypes were detected among 78 F. graminearum species complex: 15-ADON, NIV and 15-ADON+NIV. Sixty and 16 isolates represented the 15-ADON and NIV chemotypes, respectively; two isolates carried both 15-ADON and NIV-producing segments. All the isolates carrying NIV-specific segment were F. meridionale. The in vitro production of 15-ADON, 3-ADON, DON, and ZEN varied from 5.43 to 81,539.49; 6.04 to 19,590.61; 13.35 to 19,795.33; and 1.77 to 430.24 µg/g of dry hyphal weight, respectively. Altogether, our present data demonstrate potential main mycotoxin production of dominant pathogenic Fusarium in China. PMID:27338476

Monilinia Species Causing Brown Rot of Peach in China

PubMed Central

Hu, Meng-Jun; Cox, Kerik D.; Schnabel, Guido; Luo, Chao-Xi

2011-01-01

In this study, 145 peaches and nectarines displaying typical brown rot symptoms were collected from multiple provinces in China. A subsample of 26 single-spore isolates were characterized phylogenetically and morphologically to ascertain species. Phylogenetic analysis of internal transcribed spacer (ITS) regions 1 and 2, glyceraldehyde-3-phosphate dehydrogenase (G3PDH), β-tubulin (TUB2) revealed the presence of three distinct Monilinia species. These species included Monilinia fructicola, Monilia mumecola, and a previously undescribed species designated Monilia yunnanensis sp. nov. While M. fructicola is a well-documented pathogen of Prunus persica in China, M. mumecola had primarily only been isolated from mume fruit in Japan. Koch's postulates for M. mumecola and M. yunnanensis were fulfilled confirming pathogenicity of the two species on peach. Phylogenetic analysis of ITS, G3PDH, and TUB2 sequences indicated that M. yunnanensis is most closely related to M. fructigena, a species widely prevalent in Europe. Interestingly, there were considerable differences in the exon/intron structure of the cytochrome b (Cyt b) gene between the two species. Morphological characteristics, including spore size, colony morphology, lesion growth rate, and sporulation, support the phylogenetic evidence suggesting the designation of M. yunnanensis as a new species. A new multiplex PCR method was developed to facilitate the detection of M. yunnanensis and differentiation of Monilinia spp. causing brown rot of peach in China. PMID:21980371

The role of sea-ice albedo in the climate of slowly rotating aquaplanets

NASA Astrophysics Data System (ADS)

Salameh, Josiane; Popp, Max; Marotzke, Jochem

2018-04-01

We investigate the influence of the rotation period (P_{rot}) on the mean climate of an aquaplanet, with a focus on the role of sea-ice albedo. We perform aquaplanet simulations with the atmospheric general circulation model ECHAM6 for various rotation periods from one Earth-day to 365 Earth-days in which case the planet is synchronously rotating. The global-mean surface temperature decreases with increasing P_{rot} and sea ice expands equatorwards. The cooling of the mean climate with increasing P_{rot} is caused partly by the high surface albedo of sea ice on the dayside and partly by the high albedo of the deep convective clouds over the substellar region. The cooling caused by these deep convective clouds is weak for non-synchronous rotations compared to synchronous rotation. Sensitivity simulations with the sea-ice model switched off show that the global-mean surface temperature is up to 27 K higher than in our main simulations with sea ice and thus highlight the large influence of sea ice on the climate. We present the first estimates of the influence of the rotation period on the transition of an Earth-like climate to global glaciation. Our results suggest that global glaciation of planets with synchronous rotation occurs at substantially lower incoming solar irradiation than for planets with slow but non-synchronous rotation.

Extensive sampling of basidiomycete genomes demonstrates inadequacy of the white rot/ brown rot paradigm for wood decay fungi

DOE Office of Scientific and Technical Information (OSTI.GOV)

Riley, Robert; Salamov, Asaf; Brown, Daren W.

Basidiomycota (basidiomycetes) make up 32percent of the described fungi and include most wood decaying species, as well as pathogens and mutualistic symbionts. Wood-decaying basidiomycetes have typically been classified as either white rot or brown rot, based on the ability (in white rot only) to degrade lignin along with cellulose and hemicellulose. Prior genomic comparisons suggested that the two decay modes can be distinguished based on the presence or absence of ligninolytic class II peroxidases (PODs), as well as the abundance of enzymes acting directly on crystalline cellulose (reduced in brown rot). To assess the generality of the white rot/brown rotmore » classification paradigm we compared the genomes of 33 basidiomycetes, including four newly sequenced wood decayers, and performed phylogenetically-informed Principal Components Analysis (PCA) of a broad range of gene families encoding plant biomass-degrading enzymes. The newly sequenced Botryobasidium botryosum and Jaapia argillacea genomes lack PODs, but possess diverse enzymes acting on crystalline cellulose, and they group close to the model white rot species Phanerochaete chrysosporium in the PCA. Furthermore, laboratory assays showed that both B. botryosum and J. argillacea can degrade all polymeric components of woody plant cell walls, a characteristic of white rot. We also found expansions in reducing polyketide synthase genes specific to the brown rot fungi. Our results suggest a continuum rather than a dichotomy between the white rot and brown rot modes of wood decay. A more nuanced categorization of rot types is needed, based on an improved understanding of the genomics and biochemistry of wood decay.« less

Population parameters for resistance to Fusarium graminearum and Fusarium verticillioides ear rot among large sets of early, mid-late and late maturing European maize (Zea mays L.) inbred lines.

PubMed

Löffler, Martin; Kessel, Bettina; Ouzunova, Milena; Miedaner, Thomas

2010-03-01

Infection of maize ears with Fusarium graminearum (FG) and Fusarium verticillioides (FV) reduces yield and quality by mycotoxin contamination. Breeding and growing varieties resistant to both Fusarium spp. is the best alternative to minimize problems. The objectives of our study were to draw conclusions on breeding for ear rot resistance by estimating variance components, heritabilities and correlations between resistances to FV and FG severity and to investigate different inoculation methods. In 2007 and 2008, three maturity groups (early, mid-late, late) each comprising about 150 inbred lines were tested in Germany, France, Italy, and Hungary according to their maturity group. They were silk channel inoculated by FG (early) and FV (all groups). In the late maturity group, additionally kernel inoculation was applied in a separate trial. The percentage of mycelium coverage on the ear was rated at harvest (0-100%). Significant (P < 0.01) genotypic variances of ear rot severity were found in all groups. Inoculation was superior to natural infection because of higher disease severities and heritabilities. In early maturing flints and dents, FG caused significantly (P < 0.01) higher ear rot severity than FV (61.7 and 55.1% FG vs. 18.2 and 11.1% FV ear rot severity, respectively). FV inoculation in Southern Europe (mid-late, late) resulted in similar means between 10.3 and 14.0%. Selection is complicated by significant (P < 0.01) genotype x environment interactions. Correlation between FG and FV severity was moderate in flints and dents (r = 0.59 and 0.49, respectively) but lines resistant to both fungi exist. We conclude that chances for selecting improved European elite maize material within the existing germplasms is promising by multi-environmental inoculation trials.

Fungal degradation of wood lignins: Geochemical perspectives from CuO-derived phenolic dimers and monomers

NASA Astrophysics Data System (ADS)

Goñi, Miguel A.; Nelson, Bryan; Blanchette, Robert A.; Hedges, John I.

1993-08-01

The elemental compositions and yields of CuO-derived phenol dimers and monomers from woods degraded by different fungi under laboratory and natural conditions were compared to those from undegraded controls. In laboratory experiments, white-rot fungi caused pronounced mass losses, lowered the organic carbon content of the remnant woods, and decreased the absolute carbon-normalized yields of the major classes of lignin phenol dimers and monomers. White-rot decay induced large losses of some CuO reaction products, such as (β,1-diketone and α,l-monoketone dimers and syringyl monomers, and increased the absolute yields of individual acidic reaction products, such as dehydrodivanillic acid, vanillic acid, and 2-syringylsyringic acid. In contrast, the brown-rot fungus, Fomitopsis pinicola, was less efficient in decaying lignin, inducing lower absolute lignin phenol losses and, in some cases, increasing the organic carbon content of remnant woods. Several lignin constituents, mainly carboxyvanillyl monomers and α,2-methyl and α,5-monoketone dimers, were produced during brown-rot degradation. Similar diagenetic trends were also apparent in the five woods collected from the field, suggesting the differences between white- and brown-rot decay are still apparent after more extensive degradation in natural environments. The lignin compositions from a selected set of previously analyzed sedimentary mixtures were generally consistent with the diagenetic trends observed in both laboratory and field samples. In some cases, however, geochemical parameters such as elevated dimer/monomer and carboxyvanillyl/ vanillyl monomer ratios clearly distinguished certain sedimentary lignins. In these samples, other processes, such as extensive fungal decay, bacterial degradation, or a nonwoody vascular plant origin, could be important factors affecting lignin compositions.

Fengycin produced by Bacillus subtilis 9407 plays a major role in the biocontrol of apple ring rot disease.

PubMed

Fan, Haiyan; Ru, Jinjiang; Zhang, Yuanyuan; Wang, Qi; Li, Yan

2017-06-01

Apple ring rot, caused by Botryosphaeria dothidea, is a serious apple disease in China. Bacillus subtilis 9407 was isolated from healthy apples and showed strong antifungal activity against B. dothidea. To identify the primary antifungal compound of B. subtilis 9407 and determine its role in controlling apple ring rot, a transposon mutant library was constructed using TnYLB-1, and a mutant completely defective in antifungal activity was obtained. The gene inactivated in the antifungal activity mutant had 98.5% similarity to ppsB in B. subtilis subsp. subtilis str. 168, which encodes one of the five synthetases responsible for synthesizing fengycin. A markerless ppsB deletion mutant was constructed. Compared with the wild-type strain, lipopeptide crude extracts from ΔppsB showed almost no inhibition of B. dothidea mycelial growth. Furthermore, fengycin-like lipopeptides (retention factor 0.1-0.2) that exhibited antifungal activity against B. dothidea were observed in the wild-type strain by thin-layer chromatography (TLC)-bioautography analysis, but not in ΔppsB. Semipreparative reverse-phase high performance liquid chromatography (RP-HPLC) detection revealed that ΔppsB lost the ability to synthesize fengycin. These results suggest that ppsB is responsible for synthesizing fengycin and that fengycin is the major antifungal compound produced by B. subtilis 9407 against B. dothidea. Moreover, a biocontrol assay showed that the control efficacy of ΔppsB was reduced by half compared with the wild-type strain, indicating that fengycin plays a major role in controlling apple ring rot disease. This is the first report on the use of a B. subtilis strain as a potential biological control agent to control apple ring rot disease by the production of fengycin. Copyright © 2017 Elsevier GmbH. All rights reserved.

Lignin as a facilitator, not a barrier, during saccharification by brown rot fungi

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schilling, Jonathan S.; Tschirner, Ulrike; Blanchette, Robert A

2012-11-28

This research focused on the biology of a group of wood-degrading fungi that cause brown rot in wood, with particular attention to the potential to mimic this biological approach ex situ for bioprocessing lignocellulosic biomass. Supported by the long-standing theory that these fungi use a two-step oxidative/enzymatic approach during brown rot, our team’s objectives were as follows: 1) to determine the discrete timing of lignin modifications, 2) to correlate these alterations with biocatalyst efficiency and ingress into plant cell walls, and 3) to reproduce modifications prior to saccharification for efficient bioprocessing. The core findings of our research were that 1)more » lignin modifications occur nearly coincident with enzyme secretion during brown rot and 2) there is no specificity to the benefit that a brown rot pretreatment has on the efficacy of cellulases – it is a general enhancement best predicted by chemical changes to lignin and side-chain hemicellulose sugars. In our work, this meant we could attain and predict broad improvements in saccharification using commercial cellulase cocktails, in some cases more than three-fold of that in untreated biomass. This project was completed with minimal variance from the original project management plan (PMP), resulting in fourteen presentations and posters, four peer-reviewed publications, and one additional publication now in review. The publications have been valuable to other scientists working toward similar goals and have been cited in thirteen peer-reviewed publications written by others since 2010. We are working with ADM to advance application options for industry, building on the lessons learned during this DOE award period.« less

Control of Fusarium verticillioides, cause of ear rot of maize, by Pseudomonas fluorescens.

PubMed

Nayaka, Siddaiah Chandra; Shankar, Arakere C Udaya; Reddy, Munagala S; Niranjana, Siddapura R; Prakash, Harishchandra S; Shetty, Hunthrike S; Mortensen, Carmen N

2009-07-01

Maize is one of the staple food crops grown in India. Fusarium verticillioides (Sacc.) Nirenberg is the most important fungal pathogen of maize, associated with diseases such as ear rot and kernel rot. Apart from the disease, it is capable of producing fumonisins, which have elicited considerable attention over the past decade owing to their association with animal disease syndromes. Hence, the present study was conducted to evaluate ecofriendly approaches by using a maize rhizosphere isolate of Pseudomonas fluorescens (Trev.) Mig. and its formulation to control ear rot disease and fumonisin accumulation, and also to study the capacity to promote growth and yield of maize. In vitro assays were conducted to test the efficacy of P. fluorescens as a seed treatment on seed germination, seedling vigour and also the incidence of F. verticillioides in different maize cultivars. The field trials included both seed treatment and foliar spray. For all the experiments, P. fluorescens was formulated using corn starch, wheat bran and talc powder. In each case there were three different treatments of P. fluorescens, a non-treated control and chemical control. Pure culture and the formulations, in comparison with the control, increased plant growth and vigour as measured by seed germination, seedling vigour, plant height, 1000 seed weight and yield. P. fluorescens pure culture used as seed treatment and as spray treatment enhanced the growth parameters and reduced the incidence of F. verticillioides and the level of fumonisins to a maximum extent compared with the other treatments. The study demonstrates the potential role of P. fluorescens and its formulations in ear rot disease management. The biocontrol potential of this isolate is more suited for fumonisin reduction in maize kernels intended for human and animal feed. (c) 2009 Society of Chemical Industry.

Integration of soil application and seed treatment formulations of Trichoderma species for management of wet root rot of mungbean caused by Rhizoctonia solani.

PubMed

Dubey, Sunil C; Bhavani, Ranganaicker; Singh, Birendra

2011-09-01

The efficacy of seed dressing and soil application formulations from the isolates of Trichoderma viride (IARI P1; MTCC 5369), T. virens (IARI P3; MTCC 5370) and T. harzianum (IARI P4; MTCC 5371) were evaluated individually and in combination in pot and field experiments during the rainy seasons of 2005, 2006 and 2007 for the management of wet root rot (Rhizoctonia solani) and improvement in the yield of mungbean. A seed dressing formulation, Pusa 5SD, and soil application formulations, Pusa Biogranule 6 (PBG 6) and Pusa Biopellet 16G (PBP 16G), based on Trichoderma virens, were found to be superior to other formulations in reducing disease incidence and increasing seed germination and shoot and root lengths in mungbean. In field experiments, a combination of soil application with PBP 16G (T. virens) and seed treatment with Pusa 5SD (T. virens) + carboxin was superior to any of these formulations individually in increasing seed germination, shoot and root lengths and grain yield and reducing wet root rot incidence in mungbean. Seed treatment was more effective than soil application for all the evaluated parameters. The combined application of Pusa 5SD and carboxin was also superior to individual treatment. The efficacy of the evaluated formulations against wet root rot of mungbean proved that the integration of soil application of PBP 16G and seed treatment with Pusa 5SD + carboxin is highly effective for the management of wet root rot, increasing plant growth and grain yield of mungbean. Copyright © 2011 Society of Chemical Industry.

Antifungal properties of organic extracts of eight Cistus L. species against postharvest citrus sour rot.

PubMed

Karim, H; Boubaker, H; Askarne, L; Talibi, I; Msanda, F; Boudyach, E H; Saadi, B; Ait Ben Aoumar, A

2016-01-01

The effectiveness of methanol and chloroform extracts of eight Cistaceae species to control citrus sour rot decay, caused by Geotrichum citri-aurantii, was investigated in both in vitro and in vivo conditions. Methanol extracts of these plant species exhibited more interesting activity against G. citri-aurantii, in both in vitro and in vivo conditions, compared with chloroforme extracts. Under in vitro trials, obtained results showed that methanol extracts of all tested plants revealed a highest significant antifungal activity with inhibition zones that ranged between 12·33 and 16·33 mm in diameter. All tested methanol extracts totally inhibited spore germination when tested at 10 mg ml(-1) . Incidence of sour rot was significantly lowered to 11·11% when fruits were treated with Cistus populifolius and Cistus ladanifer methanol extracts compared with 100% in the control. The disease severity was lowered to 5·19% and 6·04% when fruits were treated with the same methanol extracts respectively. The methanol Cistus extracts had sufficient antifungal activities in vitro and in vivo against G. citri-aurantii to consider its use in the citrus industry after it has been tested under production and natural infection conditions. Such natural products therefore represent a viable alternative approaches for sour rot postharvest management of citrus. © 2015 The Society for Applied Microbiology.

Two different PCR approaches for universal diagnosis of brown rot and identification of Monilinia spp. in stone fruit trees.

PubMed

Gell, I; Cubero, J; Melgarejo, P

2007-12-01

To design a protocol for the universal diagnosis of brown rot by polymerase chain reaction (PCR) in plant material and subsequently Monilinia spp. identification. Primers for discrimination of Monilinia spp. from other fungal genera by PCR were designed following a ribosomal DNA analysis. Discrimination among species of Monilinia was subsequently achieved by developing primers using SCAR (Sequence Characterised Amplified Region) markers obtained after a random amplified polymorphic DNA study. In addition, an internal control (IC) based on the utilization of a mimic plasmid was designed to be used in the diagnostic protocol of brown rot to recognize false negatives due to the inhibition of PCR. The four sets of primers designed allowed detection and discrimination of all Monilinia spp. causing brown rot in fruit trees. Addition of an IC in each PCR reaction performed increased the reliability of the diagnostic protocol. The detection protocol presented here, that combined a set of universal primers and the inclusion of the plasmid pGMON as an IC for diagnosis of all Monilinia spp., and three sets of primers to discriminate the most important species of Monilinia, could be an useful and valuable tool for epidemiological studies. The method developed could be used in programmes to avoid the spread and introduction of this serious disease in new areas.

Biological control of Black Pod Disease and Seedling Blight of cacao caused by Phytophthora Species using Trichoderma from Aceh Sumatra

USDA-ARS?s Scientific Manuscript database

The cocoa tree, Theobroma cacao L., suffers large yield losses in Aceh Indonesia to the disease black pod rot, caused by Phytophthora spp. Despite having the largest area under cacao production in Sumatra, farmers in the Aceh region have low overall production because of losses to insect pests and b...

Genetic and genomic resources for mapping resistance to Phytophthora cinnamomi in chestnut

Treesearch

T. Zhebentyayeva; A. Chandra; A.G. Abbott; M.E. Staton; B.A. Olukolu; F.V. Hebard; L.L. Georgi; S.N. Jeffers; P.H. Sisco; J.B. James; C. Dana Nelson

2013-01-01

Root rot (caused by Phytophthora cinnamomi) and chestnut blight (caused by Cryphonectria parasitica) are the two most destructive diseases affecting American chestnut, Castanea dentata. Therefore, breeding for resistance to both pathogens simultaneously is essential before the American chestnut can be restored to its full native range. Using combined genetic and...

Fusarium crown rot caused by Fusarium pseudograminearum in cereal crops: recent progress and future prospects.

PubMed

Kazan, Kemal; Gardiner, Donald M

2017-11-04

Diseases caused by Fusarium pathogens inflict major yield and quality losses on many economically important plant species worldwide, including cereals. Fusarium crown rot (FCR), caused by Fusarium pseudograminearum, is a cereal disease that occurs in many arid and semi-arid cropping regions of the world. In recent years, this disease has become more prevalent, in part as a result of the adoption of moisture-preserving cultural practices, such as minimum tillage and stubble retention. In this pathogen profile, we present a brief overview of recent research efforts that have not only advanced our understanding of the interactions between F. pseudograminearum and cereal hosts, but have also provided new disease management options. For instance, significant progress has been made in the genetic characterization of pathogen populations, the development of new tools for disease prediction, and the identification and pyramiding of loci that confer quantitative resistance to FCR in wheat and barley. In addition, transcriptome analyses have revealed new insights into the processes involved in host defence. Significant progress has also been made in understanding the mechanistic details of the F. pseudograminearum infection process. The sequencing and comparative analyses of the F. pseudograminearum genome have revealed novel virulence factors, possibly acquired through horizontal gene transfer. In addition, a conserved pathogen gene cluster involved in the degradation of wheat defence compounds has been identified, and a role for the trichothecene toxin deoxynivalenol (DON) in pathogen virulence has been reported. Overall, a better understanding of cereal host-F. pseudograminearum interactions will lead to the development of new control options for this increasingly important disease problem. Taxonomy: Fusarium pseudograminearum O'Donnell & Aoki; Kingdom Fungi; Phylum Ascomycota; Subphylum Pezizomycotina; Class Sordariomycetes; Subclass Hypocreomycetidae; Order Hypocreales; Family Nectriaceae; Genus Fusarium. Disease symptoms: Fusarium crown rot caused by F. pseudograminearum is also known as crown rot, foot rot and root rot. Infected seedlings can die before or after emergence. If infected seedlings survive, typical disease symptoms are browning of the coleoptile, subcrown internode, lower leaf sheaths and adjacent stems and nodal tissues; this browning can become evident within a few weeks after planting or throughout plant development. Infected plants may develop white heads with no or shrivelled grains. Disease symptoms are exacerbated under water limitation. Identification and detection: Fusarium pseudograminearum macroconidia usually contain three to five septa (22-60.5 × 2.5-5.5 μm). On potato dextrose agar (PDA), aerial mycelia appear floccose and reddish white, with red or reddish-brown reverse pigmentation. Diagnostic polymerase chain reaction (PCR) tests based on the amplification of the gene encoding translation elongation factor-1a (TEF-1a) have been developed for molecular identification. Host range: All major winter cereals can be colonized by F. pseudograminearum. However, the main impact of this pathogen is on bread (Triticum aestivum L.) and durum (Triticum turgidum L. spp. durum (Dest.)) wheat and barley (Hordeum vulgare L.). Oats (Avena sativa L.) can be infected, but show little or no disease symptoms. In addition, the pathogen has been isolated from various other grass genera, such as Phalaris, Agropyron and Bromus, which may occur as common weeds. Useful websites: https://nt.ars-grin.gov/fungaldatabases/; http://plantpath.psu.edu/facilities/fusarium-research-center; https://nt.ars-grin.gov/fungaldatabases/; http://www.speciesfungorum.org/Names/Names.asp. © 2017 BSPP AND JOHN WILEY & SONS LTD.

In vitro decomposition of Sphagnum by some microfungi resembles white rot of wood.

PubMed

Rice, Adrianne V; Tsuneda, Akihiko; Currah, Randolph S

2006-06-01

The abilities of some ascomycetes (Myxotrichaceae) from a Sphagnum bog in Alberta to degrade cellulose, phenolics, and Sphagnum tissue were compared with those of two basidiomycetes. Most Myxotrichaceae degraded cellulose and tannic acid, and removed cell-wall components simultaneously from Sphagnum tissues, whereas the basidiomycetes degraded cellulose and insoluble phenolics, and preferentially removed the polyphenolic matrix from Sphagnum cell walls. Mass losses from Sphagnum varied from up to 50% for some ascomycetes to a maximum of 35% for the basidiomycetes. The decomposition of Sphagnum by the Myxotrichaceae was analogous to the white rot of wood and indicates that these fungi have the potential to cause significant mineralization of carbon in bogs.

Pathogenicity of Nectriaceous Fungi on Avocado in Australia.

PubMed

Parkinson, Louisamarie E; Shivas, Roger G; Dann, Elizabeth K

2017-12-01

Black root rot is a severe disease of young avocado trees in Australia causing black necrotic roots, tree stunting, and leaf drop prior to tree death. Nectriaceous fungi (Nectriaceae, Hypocreales), are commonly isolated from symptomatic roots. This research tested the pathogenicity of 19 isolates from Calonectria, Cylindrocladiella, Dactylonectria, Gliocladiopsis, and Ilyonectria, spp. collected from young avocado trees and other hosts. Glasshouse pathogenicity tests with 'Reed' avocado (Persea americana) seedlings confirmed that Calonectria ilicicola is a severe pathogen of avocado, causing stunting, wilting, and seedling death within 5 weeks of inoculation. Isolates of C. ilicicola from peanut, papaya, and custard apple were also shown to be aggressive pathogens of avocado, demonstrating a broad host range. An isolate of a Calonectria sp. from blueberry and avocado isolates of Dactylonectria macrodidyma, D. novozelandica, D. pauciseptata, and D. anthuriicola caused significant root rot but not stunting within 5 to 9 weeks of inoculation. An isolate of an Ilyonectria sp. from grapevine closely related to Ilyonectria liriodendri, and avocado isolates of Cylindrocladiella pseudoinfestans, Gliocladiopsis peggii, and an Ilyonectria sp. were not pathogenic to avocado.

Structure-based functional characterization of repressor of toxin (Rot), a central regulator of staphylococcus aureus virulence

DOE PAGES

Killikelly, April; Jakoncic, Jean; Benson, Meredith A.; ...

2014-10-20

Staphylococcus aureus is responsible for a large number of diverse infections worldwide. In order to support its pathogenic lifestyle, S. aureus has to regulate the expression of virulence factors in a coordinated fashion. One of the central regulators of the S. aureus virulence regulatory networks is the transcription factor repressor of toxin (Rot). Rot plays a key role in regulating S. aureus virulence through activation or repression of promoters that control expression of a large number of critical virulence factors. However, the mechanism by which Rot mediates gene regulation has remained elusive. Here, we have determined the crystal structure ofmore » Rot and used this information to probe the contribution made by specific residues to Rot function. Rot was found to form a dimer, with each monomer harboring a winged helix-turn-helix (WHTH) DNA-binding motif. Despite an overall acidic pI, the asymmetric electrostatic charge profile suggests that Rot can orient the WHTH domain to bind DNA. Structure-based site-directed mutagenesis studies demonstrated that R 91, at the tip of the wing, plays an important role in DNA binding, likely through interaction with the minor groove. We also found that Y 66, predicted to bind within the major groove, contributes to Rot interaction with target promoters. Evaluation of Rot binding to different activated and repressed promoters revealed that certain mutations on Rot exhibit promoter-specific effects, suggesting for the first time that Rot differentially interacts with target promoters. As a result, this work provides insight into a precise mechanism by which Rot controls virulence factor regulation in S. aureus.« less

Structure-based functional characterization of repressor of toxin (Rot), a central regulator of staphylococcus aureus virulence

DOE Office of Scientific and Technical Information (OSTI.GOV)

Killikelly, April; Jakoncic, Jean; Benson, Meredith A.

Staphylococcus aureus is responsible for a large number of diverse infections worldwide. In order to support its pathogenic lifestyle, S. aureus has to regulate the expression of virulence factors in a coordinated fashion. One of the central regulators of the S. aureus virulence regulatory networks is the transcription factor repressor of toxin (Rot). Rot plays a key role in regulating S. aureus virulence through activation or repression of promoters that control expression of a large number of critical virulence factors. However, the mechanism by which Rot mediates gene regulation has remained elusive. Here, we have determined the crystal structure ofmore » Rot and used this information to probe the contribution made by specific residues to Rot function. Rot was found to form a dimer, with each monomer harboring a winged helix-turn-helix (WHTH) DNA-binding motif. Despite an overall acidic pI, the asymmetric electrostatic charge profile suggests that Rot can orient the WHTH domain to bind DNA. Structure-based site-directed mutagenesis studies demonstrated that R 91, at the tip of the wing, plays an important role in DNA binding, likely through interaction with the minor groove. We also found that Y 66, predicted to bind within the major groove, contributes to Rot interaction with target promoters. Evaluation of Rot binding to different activated and repressed promoters revealed that certain mutations on Rot exhibit promoter-specific effects, suggesting for the first time that Rot differentially interacts with target promoters. As a result, this work provides insight into a precise mechanism by which Rot controls virulence factor regulation in S. aureus.« less

Control of black walnut root rot diseases in nurseries.

Treesearch

Kenneth J. Jr. Kessler

1982-01-01

Current nursery methods used to control black walnut root rot diseases are considered in terms of integrated pest management. Suggestions for future root rot control research studies and procedures to minimize root rot problems are provided.

Extensive sampling of basidiomycete genomes demonstrates inadequacy of the white-rot/brown-rot paradigm for wood decay fungi

Treesearch

Robert Riley; Asaf A. Salamov; Daren W. Brown; Laszlo G. Nagy; Dimitrios Floudas; Benjamin W. Held; Anthony Levasseur; Vincent Lombard; Emmanuelle Morin; Robert Otillar; Erika A. Lindquist; Hui Sun; Kurt M. LaButti; Jeremy Schmutz; Dina Jabbour; Hong Luo; Scott E. Baker; Antonio G. Pisabarro; Jonathan D. Walton; Robert A. Blanchette; Bernard Henrissat; Francis Martin; Daniel Cullen; David S. Hibbett; Igor V. Grigoriev

2014-01-01

Basidiomycota (basidiomycetes) make up 32% of the described fungi and include most wood-decaying species, as well as pathogens and mutualistic symbionts. Wood-decaying basidiomycetes have typically been classified as either white rot or brown rot, based on the ability (in white rot only) to degrade lignin along with cellulose and hemicellulose. Prior genomic...

Pyramiding Sclerotinia head rot and stalk rot resistances into elite sunflower breeding lines with the aid of DNA markers

USDA-ARS?s Scientific Manuscript database

Work was conducted in 2008 to determine the stalk rot resistance of RILs from the RHA 280 x RHA 801 population, as well as to begin introgression of previously identified QTL for head rot resistance into elite sunflower germplasm lines. The stalk rot RILs and their testcrosses with cms HA 89 were t...

Influence of tree size, taxonomy, and edaphic conditions on heart rot in mixed-dipterocarp Bornean rainforests: implications for aboveground biomass estimates

NASA Astrophysics Data System (ADS)

Heineman, K. D.; Russo, S. E.; Baillie, I. C.; Mamit, J. D.; Chai, P. P.-K.; Chai, L.; Hindley, E. W.; Lau, B.-T.; Tan, S.; Ashton, P. S.

2015-05-01

Fungal decay of heartwood creates hollows and areas of reduced wood density within the stems of living trees known as heart rot. Although heart rot is acknowledged as a source of error in forest aboveground biomass estimates, there are few datasets available to evaluate the environmental controls over heart rot infection and severity in tropical forests. Using legacy and recent data from drilled, felled, and cored stems in mixed dipterocarp forests in Sarawak, Malaysian Borneo, we quantified the frequency and severity of heart rot, and used generalized linear mixed effect models to characterize the association of heart rot with tree size, wood density, taxonomy, and edaphic conditions. Heart rot was detected in 55% of felled stems > 30 cm DBH, while the detection frequency was lower for stems of the same size evaluated by non-destructive drilling (45%) and coring (23%) methods. Heart rot severity, defined as the percent stem volume lost in infected stems, ranged widely from 0.1-82.8%. Tree taxonomy explained the greatest proportion of variance in heart rot frequency and severity among the fixed and random effects evaluated in our models. Heart rot frequency, but not severity, increased sharply with tree diameter, ranging from 56% infection across all datasets in stems > 50 cm DBH to 11% in trees 10-30 cm DBH. The frequency and severity of heart rot increased significantly in soils with low pH and cation concentrations in topsoil, and heart rot was more common in tree species associated with dystrophic sandy soils than with nutrient-rich clays. When scaled to forest stands, the percent of stem biomass lost to heart rot varied significantly with soil properties, and we estimate that 7% of the forest biomass is in some stage of heart rot decay. This study demonstrates not only that heart rot is a significant source of error in forest carbon estimates, but also that it strongly covaries with soil resources, underscoring the need to account for edaphic variation in estimating carbon storage in tropical forests.

Fungicidal activity of essential oils of Cinnamomum zeylanicum (L.) and Syzygium aromaticum (L.) Merr et L.M. Perry against crown rot and anthracnose pathogens isolated from banana.

PubMed

Ranasinghe, L; Jayawardena, B; Abeywickrama, K

2002-01-01

To develop a post-harvest treatment system against post-harvest fungal pathogens of banana using natural products. Colletotrichum musae was isolated and identified as the causative agent responsible for anthracnose peel blemishes while three fungi, namely Lasiodiplodia theobromae, C. musae and Fusarium proliferatum, were identified as causative agents responsible for crown rot. During the liquid bioassay, cinnamon [Cinnamomum zeylanicum (L.)] leaf, bark and clove [Syzygium aromaticum (L.)] oils were tested against the anthracnose and crown rot pathogens. The test oils were fungistatic and fungicidal against the test pathogens within a range of 0.03-0.11% (v/v). Cinnamon and clove essential oils could be used as antifungal agents to manage post harvest fungal diseases of banana. Cinnamon and clove essential oil could be used as alternative post-harvest treatments on banana. Banana treated with essential oil is chemically safe and acceptable to consumers. Benomyl (Benlate), which is currently used to manage fungal pathogens, can cause adverse health effects and could be replaced with volatile essential oils.

Trehalose-related gene deletions in Fusarium verticillioides

USDA-ARS?s Scientific Manuscript database

Fusarium verticillioides is a widespread corn pathogen that causes root, stalk, and ear rot and produces fumonisins, toxic secondary metabolites associated with disease in livestock and humans. Our goal is to assess the feasibility of exploiting trehalose metabolism as a target for F. verticillioide...

Trehalose-related Gene Deletions in Fusarium verticillioides

USDA-ARS?s Scientific Manuscript database

Fusarium verticillioides is a widespread corn pathogen that causes root, stalk and ear rot and produces fumonisins, toxic secondary metabolites associated with disease in livestock and humans. Our goal is to assess the feasibility of exploiting trehalose metabolism as a target for F. verticillioides...

Causes and effects of poor drainage in cranberry farms

USDA-ARS?s Scientific Manuscript database

Soils that support the growth of cranberries often cap geologic deposits of organic sediment, such as peat. However, low-permeability organic sediments may result in inadequate drainage that diminishes plant productivity and enhances fruit rot. Consequently, new constructions of cranberry farms are ...

A new approach for strawberry disease control

USDA-ARS?s Scientific Manuscript database

Strawberry is grown around the world in different production systems and diverse environmental conditions, which creates challenges in controlling fruit-rot causing pathogens before and after harvest. Fungicides have been traditionally used to control these diseases, and in some areas, as many as 2...

Phylogenetic, Morphological, and Pathogenic Characterization of Alternaria Species Associated with Fruit Rot of Blueberry in California.

PubMed

Zhu, X Q; Xiao, C L

2015-12-01

Fruit rot caused by Alternaria spp. is one of the most important factors affecting the postharvest quality and shelf life of blueberry fruit. The aims of this study were to characterize Alternaria isolates using morphological and molecular approaches and test their pathogenicity to blueberry fruit. Alternaria spp. isolates were collected from decayed blueberry fruit in the Central Valley of California during 2012 and 2013. In total, 283 isolates were obtained and five species of Alternaria, including Alternaria alternata, A. tenuissima, A. arborescens, A. infectoria, and A. rosae, were identified based on DNA sequences of the plasma membrane ATPase, Alt a1 and Calmodulin gene regions in combination with morphological characters of the culture and sporulation. Of the 283 isolates, 61.5% were identified as A. alternata, 32.9% were A. arborescens, 5.0% were A. tenuissima, and only one isolate of A. infectoria and one isolate of A. rosae were found. These fungi were able to grow at temperatures from 0 to 35°C, and mycelial growth was arrested at 40°C. Optimal radial growth occurred between 20 to 30°C. Pathogenicity tests showed that all five Alternaria spp. were pathogenic on blueberry fruit at 0, 4, and 20°C, with A. alternata, A. arborescens, and A. tenuissima being the most virulent species, followed by A. infectoria and A. rosae. Previously A. tenuissima has been reported to be the primary cause of Alternaria fruit rot of blueberry worldwide. Our results indicated that the species composition of Alternaria responsible for Alternaria fruit rot in blueberry can be dependent on geographical region. A. alternata, A. arborescens, A. infectoria, and A. rosae are reported for the first time on blueberry in California. This is also the first report of A. infectoria and A. rosae infecting blueberry fruit.

Integrated options for the management of black root rot of strawberry caused by Rhizoctonia solani Kuhn.

PubMed

Asad-Uz-Zaman, Md; Bhuiyan, Mohammad Rejwan; Khan, Mohammad Ashik Iqbal; Alam Bhuiyan, Md Khurshed; Latif, Mohammad Abdul

2015-02-01

An investigation was made to manage strawberry black root rot caused by Rhizoctonia solani (R. solani) through the integration of Trichoderma harzianum (T. harzianum) isolate STA7, mustard oil cake and Provax 200. A series of preliminary experiments were conducted to select a virulent isolate of R. solani, an effective isolate of T. harzianum, a suitable organic amendment, and a suitable fungicide before setting the experiment for integration. The pathogenicity of the selected four isolates of R. solani was evaluated against strawberry and isolate SR1 was selected as the test pathogen due to its highest virulent (95.47% mortality) characteristics. Among the 20 isolates of T. harzianum, isolate STA7 showed maximum inhibition (71.97%) against the test pathogen (R. solani). Among the fungicides, Provax-200 was found to be more effective at lowest concentration (100 ppm) and highly compatible with Trichoderma isolates STA7. In the case of organic amendments, maximum inhibition (59.66%) of R. solani was obtained through mustard oil cake at the highest concentration (3%), which was significantly superior to other amendments. Minimum percentages of diseased roots were obtained with pathogen (R. solani)+Trichoderma+mustard oil cake+Provax-200 treatment, while the highest was observed with healthy seedlings with a pathogen-inoculated soil. In the case of leaf and fruit rot diseases, significantly lowest infected leaves as well as fruit rot were observed with a pathogen+Trichoderma+mustard oil cake+Provax-200 treatment in comparison with the control. A similar trend of high effectiveness was observed by the integration of Trichoderma, fungicide and organic amendments in controlling root rot and fruit diseases of strawberry. Single application of Trichoderma isolate STA7, Provax 200 or mustard oil cake did not show satisfactory performance in terms of disease-free plants, but when they were applied in combination, the number of healthy plants increased significantly. The result of the current study suggests the superiority of our integrated approach to control the sclerotia forming pathogen R. solani compared to the individual treatment either by an antagonist or by a fungicide or by mustard oil cake. Copyright © 2014 Académie des sciences. Published by Elsevier SAS. All rights reserved.

Cell wall integrity modulates RHO1 activity via the exchange factor ROM2.

PubMed Central

Bickle, M; Delley, P A; Schmidt, A; Hall, M N

1998-01-01

The essential phosphatidylinositol kinase homologue TOR2 of Saccharomyces cerevisiae controls the actin cytoskeleton by activating a GTPase switch consisting of RHO1 (GTPase), ROM2 (GEF) and SAC7 (GAP). We have identified two mutations, rot1-1 and rot2-1, that suppress the loss of TOR2 and are synthetic-lethal. The wild-type ROT1 and ROT2 genes and a multicopy suppressor, BIG1, were isolated by their ability to rescue the rot1-1 rot2-1 double mutant. ROT2 encodes glucosidase II, and ROT1 and BIG1 encode novel proteins. We present evidence that cell wall defects activate RHO1. First, rot1, rot2, big1, cwh41, gas1 and fks1 mutations all confer cell wall defects and suppress tor2(ts). Second, destabilizing the cell wall by supplementing the growth medium with 0.005% SDS also suppresses a tor2(ts) mutation. Third, disturbing the cell wall with SDS or a rot1, rot2, big1, cwh41, gas1 or fks1 mutation increases GDP/GTP exchange activity toward RHO1. These results suggest that cell wall defects suppress a tor2 mutation by activating RHO1 independently of TOR2, thereby inducing TOR2-independent polarization of the actin cytoskeleton and cell wall synthesis. Activation of RHO1, a subunit of the cell wall synthesis enzyme glucan synthase, by a cell wall alteration would ensure that cell wall synthesis occurs only when and where needed. The mechanism of RHO1 activation by a cell wall alteration is via the exchange factor ROM2 and could be analogous to signalling by integrin receptors in mammalian cells. PMID:9545237

Cannabinoid Type 2 (CB2) Receptors Activation Protects against Oxidative Stress and Neuroinflammation Associated Dopaminergic Neurodegeneration in Rotenone Model of Parkinson's Disease

PubMed Central

Javed, Hayate; Azimullah, Sheikh; Haque, M. Emdadul; Ojha, Shreesh K.

2016-01-01

The cannabinoid type two receptors (CB2), an important component of the endocannabinoid system, have recently emerged as neuromodulators and therapeutic targets for neurodegenerative diseases including Parkinson's disease (PD). The downregulation of CB2 receptors has been reported in the brains of PD patients. Therefore, both the activation and the upregulation of the CB2 receptors are believed to protect against the neurodegenerative changes in PD. In the present study, we investigated the CB2 receptor-mediated neuroprotective effect of β-caryophyllene (BCP), a naturally occurring CB2 receptor agonist, in, a clinically relevant, rotenone (ROT)-induced animal model of PD. ROT (2.5 mg/kg BW) was injected intraperitoneally (i.p.) once daily for 4 weeks to induce PD in male Wistar rats. ROT injections induced a significant loss of dopaminergic (DA) neurons in the substantia nigra pars compacta (SNpc) and DA striatal fibers, following activation of glial cells (astrocytes and microglia). ROT also caused oxidative injury evidenced by the loss of antioxidant enzymes and increased nitrite levels, and induction of proinflammatory cytokines: IL-1β, IL-6 and TNF-α, as well as inflammatory mediators: NF-κB, COX-2, and iNOS. However, treatment with BCP attenuated induction of proinflammatory cytokines and inflammatory mediators in ROT-challenged rats. BCP supplementation also prevented depletion of glutathione concomitant to reduced lipid peroxidation and augmentation of antioxidant enzymes: SOD and catalase. The results were further supported by tyrosine hydroxylase immunohistochemistry, which illustrated the rescue of the DA neurons and fibers subsequent to reduced activation of glial cells. Interestingly, BCP supplementation demonstrated the potent therapeutic effects against ROT-induced neurodegeneration, which was evidenced by BCP-mediated CB2 receptor activation and the fact that, prior administration of the CB2 receptor antagonist AM630 diminished the beneficial effects of BCP. The present study suggests that BCP has the potential therapeutic efficacy to elicit significant neuroprotection by its anti-inflammatory and antioxidant activities mediated by activation of the CB2 receptors. PMID:27531971

Energy balance associated with the degradation of lignocellulosic material by white-rot and brown-rot fungi.

NASA Astrophysics Data System (ADS)

Derrien, Delphine; Bédu, Hélène; Buée, Marc; Kohler, Annegret; Goodell, Barry; Gelhaye, Eric

2017-04-01

Forest soils cover about 30% of terrestrial area and comprise between 50 and 80% of the global stock of soil organic carbon (SOC). The major precursor for this forest SOC is lignocellulosic material, which is made of polysaccharides and lignin. Lignin has traditionally been considered as a recalcitrant polymer that hinders access to the much more labile structural polysaccharides. This view appears to be partly incorrect from a microbiology perspective yet, as substrate alteration depends on the metabolic potential of decomposers. In forest ecosystems the wood-rotting Basidiomycota fungi have developed two different strategies to attack the structure of lignin and gain access to structural polysaccharides. White-rot fungi degrade all components of plant cell walls, including lignin, using enzymatic systems. Brown-rot fungi do not remove lignin. They generate oxygen-derived free radicals, such as the hydroxyl radical produced by the Fenton reaction, that disrupt the lignin polymer and depolymerize polysaccharides which then diffuse out to where the enzymes are located The objective of this study was to develop a model to investigate whether the lignin relative persistence could be related to the energetic advantage of brown-rot degradative pathway in comparison to white-rot degradative pathway. The model simulates the changes in substrate composition over time, and determines the energy gained from the conversion of the lost substrate into CO2. The energy cost for the production of enzymes involved in substrate alteration is assessed using information derived from genome and secretome analysis. For brown-rot fungus specifically, the energy cost related to the production of OH radicals is also included. The model was run, using data from the literature on populous wood degradation by Trametes versicolor, a white-rot fungus, and Gloeophyllum trabeum, a brown-rot fungus. It demonstrates that the brown-rot fungus (Gloeophyllum trabeum) was more efficient than the white-rot fungus (Trametes versicolor). The energy advantage could explain the emergence of the brown-rot degradative pathway from a white-rot degradative pathway and subsequently, the relative persistence of lignin in soil.

Association of Neonectria macrodidyma with dry root rot of citrus in California

USDA-ARS?s Scientific Manuscript database

The fungal genus Cylindrocarpon (teleomorph: Neonectria Wolenw.) include ubiquitous soilborne pathogens that cause black foot disease on a wide range of hosts, including grapevine, strawberry, apple, and conifers. Hosts typically become infected through natural wounds on roots and other below ground...

Evaluation of soybean genotypes for resistance to three seed borne diseases

USDA-ARS?s Scientific Manuscript database

Seed-borne diseases of soybeans caused by Phomopsis longicolla (Phomopsis seed decay), Cercospora kukuchii (purple seed stain), and M. phaseolina (charcoal rot) are economically important seed-borne diseases that affect seed quality. Commercial cultivars marketed as resistant to all the three disea...

Introduction to Oomycetes

USDA-ARS?s Scientific Manuscript database

The oomycetes, also known as “water molds”, are a group of several hundred organisms that include some of the most devastating plant pathogens. The diseases they cause include seedling blights, damping-off, root rots, foliar blights and downy mildews. Some notable diseases are the late blight of po...

Fungitoxicity of some higher plants and synergistic activity of their essential oils against Sclerotium rolfsii sacc. causing foot-rot disease of barley.

PubMed

Singh, R K

Twenty five plant species were screened for their volatile components against hyphal growth and sclerotia formation of Sclerotium rolfsii causing foot rot disease of barley (Hordeum vulgare). Leaves of Chenopodium ambrosioides (CA), Lippia alba (LA), Azadirachta indica (AI) and Eucalyptus globulus (EG) were found to be strongly toxic. Their volatile active factors were isolated in the form of essential oils which were tested for toxicity individually and in six combinations (1:1 v/v) viz. CA-LA, LA-AI, CA-AI, CA-EG, and EG-AI. The oil combinations were found to be more fungitoxic than the individual oils. The CA-LA, LA-AI, EG-AI, and CA-EG combinations exhibited a broad fnngitoxic spectrum while CA-AI, LA-EG combinations possessed a narrow range of toxicity. None of the six oil combinations showed phytotoxic behaviour on seed germination, seedling growth and general morphology of Hordeum vulgare.

Pathogen profile update: Fusarium oxysporum.

PubMed

Michielse, Caroline B; Rep, Martijn

2009-05-01

Kingdom Fungi; Phylum Ascomycota; Class Sordariomycetes; Order Hypocreales; Family Nectriaceae; genus Fusarium. Very broad at the species level. More than 120 different formae speciales have been identified based on specificity to host species belonging to a wide range of plant families. Initial symptoms of vascular wilt include vein clearing and leaf epinasty, followed by stunting, yellowing of the lower leaves, progressive wilting, defoliation and, finally, death of the plant. On fungal colonization, the vascular tissue turns brown, which is clearly visible in cross-sections of the stem. Some formae speciales are not primarily vascular pathogens, but cause foot and root rot or bulb rot. Can cause severe losses in many vegetables and flowers, field crops, such as cotton, and plantation crops, such as banana, date palm and oil palm. Use of resistant varieties is the only practical measure for controlling the disease in the field. In glasshouses, soil sterilization can be performed. http://www.broad.mit.edu/annotation/genome/fusarium_group/MultiHome.html; http://www.fgsc.net/Fusarium/fushome.htm; http://www.phi-base.org/query.php

Low doses of gamma radiation in the management of postharvest Lasiodiplodia theobromae in mangos

PubMed Central

Santos, Alice Maria Gonçalves; Lins, Severina Rodrigues Oliveira; da Silva, Josenilda Maria; de Oliveira, Sônia Maria Alves

2015-01-01

The postharvest life of mango is limited by the development of pathogens, especially fungi that cause rot, among which stands out the Lasiodiplodia theobromae. Several control methods have been employed to minimize the damages caused by this fungus, chemical control can leave residues to man and nature; physical control by the use of gamma radiation in combination with modified atmosphere and cold storage. The use of gamma radiation helps to reduce the severity of the pathogen assist in the ripening process of fruits, even at low doses (0.25, 0.35 and 0.45 kGy) chemical properties such as pH, soluble solids, acid ascorbic, titratable acidity and also the quality parameters of the pulp showed no damage that are ideal for trade and consumption of mangoes. This treatment can be extended for use in the management of diseases such as natural infections for penducular rot complex that has as one of L. theobroma pathogens involved. PMID:26413068

Integrated management of foot rot of lentil using biocontrol agents under field condition.

PubMed

Hannan, M A; Hasan, M M; Hossain, I; Rahman, S M E; Ismail, Alhazmi Mohammed; Oh, Deog-Hwan

2012-07-01

The efficacy of cowdung, Bangladesh Institute of Nuclear Agriculture (BINA)-biofertilizer, and Bangladesh Agricultural University (BAU)-biofungicide, alone or in combination, was evaluated for controlling foot rot disease of lentil. The results exhibited that BINA-biofertilizer and BAUbiofungicide (peat soil-based Rhizobium leguminosarum and black gram bran-based Trichoderma harzianum) are compatible and have combined effects in controlling the pathogenic fungi Fusarium oxysporum and Sclerotium rolfsii, which cause the root rot of lentil. Cowdung mixing with soil (at 5 t/ha) during final land preparation and seed coating with BINA-biofertilizer and BAU-biofungicide (at 2.5% of seed weight) before sowing recorded 81.50% field emergence of lentil, which showed up to 19.85% higher field emergence over the control. Post-emergence deaths of plants due to foot rot disease were significantly reduced after combined seed treatment with BINA-biofertilizer and BAU-biofungicide. Among the treatments used, only BAU-biofungicide as the seed treating agent resulted in higher plant stand (84.82%). Use of BINA-biofertilizer and BAU-biofungicide as seed treating biocontrol agents and application of cowdung in the soil as an organic source of nutrient resulted in higher shoot and root lengths, and dry shoot and root weights of lentil. BINA-biofertilizer significantly increased the number of nodules per plant and nodules weight of lentil. Seeds treating with BAUbiofungicide and BINA-biofertilizer and soil amendment with cowdung increased the biomass production of lentil up to 75.56% over the control.

Shade tree spatial structure and pod production explain frosty pod rot intensity in cacao agroforests, Costa Rica.

PubMed

Gidoin, Cynthia; Avelino, Jacques; Deheuvels, Olivier; Cilas, Christian; Bieng, Marie Ange Ngo

2014-03-01

Vegetation composition and plant spatial structure affect disease intensity through resource and microclimatic variation effects. The aim of this study was to evaluate the independent effect and relative importance of host composition and plant spatial structure variables in explaining disease intensity at the plot scale. For that purpose, frosty pod rot intensity, a disease caused by Moniliophthora roreri on cacao pods, was monitored in 36 cacao agroforests in Costa Rica in order to assess the vegetation composition and spatial structure variables conducive to the disease. Hierarchical partitioning was used to identify the most causal factors. Firstly, pod production, cacao tree density and shade tree spatial structure had significant independent effects on disease intensity. In our case study, the amount of susceptible tissue was the most relevant host composition variable for explaining disease intensity by resource dilution. Indeed, cacao tree density probably affected disease intensity more by the creation of self-shading rather than by host dilution. Lastly, only regularly distributed forest trees, and not aggregated or randomly distributed forest trees, reduced disease intensity in comparison to plots with a low forest tree density. A regular spatial structure is probably crucial to the creation of moderate and uniform shade as recommended for frosty pod rot management. As pod production is an important service expected from these agroforests, shade tree spatial structure may be a lever for integrated management of frosty pod rot in cacao agroforests.

Antibiotic-producing Pseudomonas fluorescens mediates rhizome rot disease resistance and promotes plant growth in turmeric plants.

PubMed

Prabhukarthikeyan, S R; Keerthana, U; Raguchander, T

2018-05-01

Rhizome rot of turmeric caused by Pythium aphanidermatum is a major threat to turmeric-cultivating areas of India. This study intends to evaluate the performance of fluorescent pseudomonads against Rhizome rot disease and understand the resistance mechanism in Turmeric plants. Fluorescent pseudomonads were screened against Pythium aphanidermatum using dual culture. Selected strains were evaluated for the performance of growth promoting attributes and the presence of antibiotic genes through PCR analysis. Strain FP7 recorded the maximum percent inhibition of P. aphanidermatum under in vitro conditions. Strains FP7 and TPF54 both increased plant growth in turmeric plants in vitro. Strain FP7 alone contained all the evaluated antibiotic biosynthetic genes. Talc and liquid-based formulations were prepared with effective strain and tested for its biocontrol activities under both glasshouse and field conditions. Enzymatic activities of the induced defense enzymes such as PO, PPO, PAL, CAT and SOD were estimated and subjected to spectrophotometric analysis. A combination of rhizome dip and soil drench of FP7 liquid formulation treatment remarkably recorded the minimum disease incidence, higher defense enzymes, maximum plant growth and yield under glasshouse and field conditions. Application of strain FP7 increased the defense molecules, plant growth and yield in turmeric plants thereby reducing the incidence of rhizome rot disease. Moreover, this study has a potential to be adopted for sustainable and eco-friendly turmeric production. Copyright © 2018 Elsevier GmbH. All rights reserved.

Impacts of fungal stalk rot pathogens on physicochemical properties of sorghum grain

USDA-ARS?s Scientific Manuscript database

Stalk rot diseases are among the most ubiquitous and damaging fungal diseases of sorghum worldwide. Although reports of quantitative stalk rot yield losses are available, the impact of stalk rot on the physicochemical attributes of sorghum grain is currently unknown. This study was conducted to test...

7 CFR 29.6039 - Stem rot.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Stem rot. 29.6039 Section 29.6039 Agriculture... INSPECTION Standards Definitions § 29.6039 Stem rot. The deterioration of an uncured or frozen stem resulting from bacterial action. Although stem rot results from bacterial action, it is inactive in cured tobacco...

7 CFR 29.6039 - Stem rot.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 2 2014-01-01 2014-01-01 false Stem rot. 29.6039 Section 29.6039 Agriculture... INSPECTION Standards Definitions § 29.6039 Stem rot. The deterioration of an uncured or frozen stem resulting from bacterial action. Although stem rot results from bacterial action, it is inactive in cured tobacco...

7 CFR 29.6039 - Stem rot.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 2 2011-01-01 2011-01-01 false Stem rot. 29.6039 Section 29.6039 Agriculture... INSPECTION Standards Definitions § 29.6039 Stem rot. The deterioration of an uncured or frozen stem resulting from bacterial action. Although stem rot results from bacterial action, it is inactive in cured tobacco...

7 CFR 29.6039 - Stem rot.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 2 2013-01-01 2013-01-01 false Stem rot. 29.6039 Section 29.6039 Agriculture... INSPECTION Standards Definitions § 29.6039 Stem rot. The deterioration of an uncured or frozen stem resulting from bacterial action. Although stem rot results from bacterial action, it is inactive in cured tobacco...

7 CFR 29.6039 - Stem rot.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 2 2012-01-01 2012-01-01 false Stem rot. 29.6039 Section 29.6039 Agriculture... INSPECTION Standards Definitions § 29.6039 Stem rot. The deterioration of an uncured or frozen stem resulting from bacterial action. Although stem rot results from bacterial action, it is inactive in cured tobacco...

Aerial photography for sensing plant anomalies

NASA Technical Reports Server (NTRS)

Gausman, H. W.; Cardenas, R.; Hart, W. G.

1970-01-01

Changes in the red tonal response of Kodak Ektrachrome Infrared Aero 8443 film (EIR) are often incorrectly attributed solely to variations in infrared light reflectance of plant leaves, when the primary influence is a difference in visible light reflectance induced by varying chlorophyll contents. Comparisons are made among aerial photographic images of high- and low-chlorophyll foliage. New growth, foot rot, and boron and chloride nutrient toxicites produce low-chlorophyll foliage, and EIR transparency images of light red or white compared with dark-red images of high-chlorophyll foliage. Deposits of the sooty mold fungus that subsists on the honeydew produced by brown soft scale insects, obscure the citrus leaves' green color. Infected trees appear as black images on EIR film transparencies compared with red images of healthy trees.

Investigations of biodeterioration by fungi in historic wooden churches of Chiloé, Chile.

PubMed

Ortiz, Rodrigo; Párraga, Mario; Navarrete, José; Carrasco, Ivo; de la Vega, Eduardo; Ortiz, Manuel; Herrera, Paula; Jurgens, Joel A; Held, Benjamin W; Blanchette, Robert A

2014-04-01

The use of wood in construction has had a long history and Chile has a rich cultural heritage of using native woods for building churches and other important structures. In 2000, UNESCO designated a number of the historic churches of Chiloé, built entirely of native woods, as World Heritage Sites. These unique churches were built in the late 1700 s and throughout the 1800 s, and because of their age and exposure to the environment, they have been found to have serious deterioration problems. Efforts are underway to better understand these decay processes and to carryout conservation efforts for the long-term preservation of these important structures. This study characterized the types of degradation taking place and identified the wood decay fungi obtained from eight historic churches in Chiloé, seven of them designated as UNESCO World Heritage sites. Micromorphological observations identified white, brown and soft rot in the structural woods and isolations provided pure cultures of fungi that were identified by sequencing of the internal transcribed region of rDNA. Twenty-nine Basidiomycota and 18 Ascomycota were found. These diverse groups of fungi represent several genera and species not previously reported from Chile and demonstrates a varied microflora is causing decay in these historic buildings.

Gene Deletion and Functional Analysis of Fusarium verticillioides Trehalose Metabolism

USDA-ARS?s Scientific Manuscript database

Fusarium verticillioides is a species of fungus that causes stalk, ear, and kernel rot of corn and produces fumonisins, a group of mycotoxins that have dangerous health effects. We have observed previously that the intracellular concentration of trehalose, a disaccharide involved in resistance to st...

Testing and implementing methods for managing Phytophthora root diseases in California native habitats and restoration sites

Treesearch

Tedmund J. Swiecki; Elizabeth A. Bernhardt

2017-01-01

Over the past 14 years, a variety of native plant communities in northern California have been identified where introduced root-rotting Phytophthora species, most notably Phytophthora cinnamomi, P. cambivora, and P. cactorum, are causing decline and mortality of...

Effect of chemical cues on the foraging and tunneling behavior of Formosan subterranean termites (Isoptera: Rhinotermitidae)

USDA-ARS?s Scientific Manuscript database

Wood rot fungi can cause directional tunneling, aggregation behavior and increased wood consumption by subterranean termites. Because vanillin and guaiacol are byproducts of lignin degradation, these chemicals were tested as potential attractants to Formosan subterranean termites, Coptotermes formo...

Change and Children.

ERIC Educational Resources Information Center

Ostlund, Karen; Fite, Kathy

1988-01-01

Describes classroom activities to help children determine cause and relate the changes to the substances being changed. Advocates the use of "change jars" and making daily observations to teach the concepts that certain conditions promote change. Includes ideas using temperature, moisture, rotting, and sprouting to teach the concept of change. (CW)

Combination of RNAseq and SNP nanofluidic array reveals the center of genetic diversity of cacao pathogen Moniliophthora roreri in the upper Magdalena Valley of Colombia and its clonality

USDA-ARS?s Scientific Manuscript database

Moniliophthora roreri is the fungal pathogen that causes frosty pod rot (FPR) disease of Theobroma cacao L., the source of chocolate. FPR occurs in most of the cacao producing countries in the Western Hemisphere, causing yield losses up to 80%. Genetic diversity within the FPR pathogen population ma...

Overexpression of BSR1 confers broad-spectrum resistance against two bacterial diseases and two major fungal diseases in rice

PubMed Central

Maeda, Satoru; Hayashi, Nagao; Sasaya, Takahide; Mori, Masaki

2016-01-01

Broad-spectrum disease resistance against two or more types of pathogen species is desirable for crop improvement. In rice, Xanthomonas oryzae pv. oryzae (Xoo), the causal bacteria of rice leaf blight, and Magnaporthe oryzae, the fungal pathogen causing rice blast, are two of the most devastating pathogens. We identified the rice BROAD-SPECTRUM RESISTANCE 1 (BSR1) gene for a BIK1-like receptor-like cytoplasmic kinase using the FOX hunting system, and demonstrated that BSR1-overexpressing (OX) rice showed strong resistance to the bacterial pathogen, Xoo and the fungal pathogen, M. oryzae. Here, we report that BSR1-OX rice showed extended resistance against two other different races of Xoo, and to at least one other race of M. oryzae. In addition, the rice showed resistance to another bacterial species, Burkholderia glumae, which causes bacterial seedling rot and bacterial grain rot, and to Cochliobolus miyabeanus, another fungal species causing brown spot. Furthermore, BSR1-OX rice showed slight resistance to rice stripe disease, a major viral disease caused by rice stripe virus. Thus, we demonstrated that BSR1-OX rice shows remarkable broad-spectrum resistance to at least two major bacterial species and two major fungal species, and slight resistance to one viral pathogen. PMID:27436950

Overexpression of BSR1 confers broad-spectrum resistance against two bacterial diseases and two major fungal diseases in rice.

PubMed

Maeda, Satoru; Hayashi, Nagao; Sasaya, Takahide; Mori, Masaki

2016-06-01

Broad-spectrum disease resistance against two or more types of pathogen species is desirable for crop improvement. In rice, Xanthomonas oryzae pv. oryzae (Xoo), the causal bacteria of rice leaf blight, and Magnaporthe oryzae, the fungal pathogen causing rice blast, are two of the most devastating pathogens. We identified the rice BROAD-SPECTRUM RESISTANCE 1 (BSR1) gene for a BIK1-like receptor-like cytoplasmic kinase using the FOX hunting system, and demonstrated that BSR1-overexpressing (OX) rice showed strong resistance to the bacterial pathogen, Xoo and the fungal pathogen, M. oryzae. Here, we report that BSR1-OX rice showed extended resistance against two other different races of Xoo, and to at least one other race of M. oryzae. In addition, the rice showed resistance to another bacterial species, Burkholderia glumae, which causes bacterial seedling rot and bacterial grain rot, and to Cochliobolus miyabeanus, another fungal species causing brown spot. Furthermore, BSR1-OX rice showed slight resistance to rice stripe disease, a major viral disease caused by rice stripe virus. Thus, we demonstrated that BSR1-OX rice shows remarkable broad-spectrum resistance to at least two major bacterial species and two major fungal species, and slight resistance to one viral pathogen.

Preservation of hyphal-forming brown- and white-rot wood-inhabiting basidiomycetes

Treesearch

Suki C. Croan

2001-01-01

Lyophilization is an excellent technique for the long-term preservation of hyphal-forming brown-and white-rot wood-inhabiting basidiomycotina. However, vegetative mycelial isolates are not lyophilizable. In this study, 10 brown-rot and 10 white-rot basidiomycetous non-sporulating, non-chlamydosporulating, and non-bubillerferous basidiomycetes fungi were tested for...

First report of Colletotrichum nigrum causing anthracnose disease on tomato fruit in New Jersey

USDA-ARS?s Scientific Manuscript database

Anthracnose fruit rot is one of the most serious diseases affecting the production of tomato (Solanum lycopersicum L.) in the United States and is typically incited by Colletotrichum coccodes, C. gloeosporioides or C. dematium (Farr and Rossman 2016). During the summer of 2013, symptoms characteris...

Working with anaerobic soil disinfestation for control of key soil-borne pathogens

USDA-ARS?s Scientific Manuscript database

Anaerobic soil disinfestation (ASD) has been shown to be effective in reducing Verticillium dahliae in soil and to be able to provide marketable fruit yields compatible to fumigation in California strawberry systems. However the effect of ASD on charcoal rot caused by Macrophomina phaseolina in Cali...

Postharvest respiration rate and sucrose content of Rhizoctonia-infected sugarbeet roots

USDA-ARS?s Scientific Manuscript database

Rhizotonia crown and root rot of sugarbeet (Beta vulgaris L), caused by Rhizoctonia solani AG 2-2, is increasing in Minnesota and North Dakota. As the disease increases in prevalence and severity, more diseased roots are being stored in piles where they affect storability and postharvest quality. T...

Postharvest respiration rate and sucrose content of Rhizoctonia-infected sugarbeet roots

USDA-ARS?s Scientific Manuscript database

Rhizotonia crown and root rot of sugarbeet, caused by Rhizoctonia solani AG 2-2, is increasing in Minnesota and North Dakota. As the disease increases in prevalence and severity, more diseased roots are being stored in piles where they affect storability and postharvest quality. The objective of th...

Phytophthora tentaculata

Treesearch

Suzanne Rooney-Latham; Cheryl Blomquist; Ted Swiecki; Elizabeth Bernhardt

2015-01-01

Phytophthora tentaculata Kröber & Marwitz was described in 1993 in Germany on greenhouse-grown nursery ornamentals. It has since been found in Italy, Spain, China and the U.S. (California) causing a root and stem rot of many different plant species including nursery-grown native species used for habitat restoration. P. tentaculata...

Fungicide resistance profiles for 13 Botrytis cinerea isolated from strawberry in southeastern Louisiana

USDA-ARS?s Scientific Manuscript database

BACKGROUND: Fungicidal sprays have been widely used for disease control of gray mold caused by Botrytis cinerea. In recent years strawberry growers in southeastern Louisiana reported a failure of their fungicide spray programs to control Botrytis fruit rot. Botrytis cinerea has become resistant ...

First report of root rot of Chicory caused by Phytophthora cryptogea in Chile

USDA-ARS?s Scientific Manuscript database

Chicory (Cichorium intybus L. var sativum Bisch.), a relatively new high value crop in Chile, was introduced for commercial production of inulin. Inulins are polysaccharides extracted from chicory tap roots that are used in processed foods due to their beneficial gastrointestinal properties. Approxi...

Colonization of Clonostachys rosea on soybean root inoculated with Fusarium graminearum

USDA-ARS?s Scientific Manuscript database

Soybean root rot, caused by Fusarium graminearum, is a devastating disease. Clonostachys rosea has been reported to have protection against plant pathogens in different crops. The objectives of this study were to determine if a strain of C. rosea (ACM941) can colonize soybean root that were inocula...

Evaluation of phosphonate treatments for control of phytophthora crown rot of walnut

USDA-ARS?s Scientific Manuscript database

Foliar and soil applications of phosphonate were evaluated in a factorial manner for control of trunk cankers caused by Phytophthora citricola in a Persian walnut orchard, cultivar ‘Chandler’. In each of two experiments, the foliar treatment was applied once in the second week of September, whereas...

A new species of Laetiporus (Basidiomycota, Polyporales) from the Caribbean basin

Treesearch

Mark T. Banik; Daniel L. Lindner; Beatriz Ortiz-Santana; Deborah J. Lodge

2012-01-01

Laetiporus caribensis is described as a new species, causing brown rot on hardwoods in the Caribbean basin. Laetiporus caribensis is distinguished from described species in the genus by smaller basidiospores. In addition, single spore isolates of L. caribensis are incompatible with those of the known species of...

RECONSTRUCTING THE EVOLUTIONARY HISTORY OF THE FOREST FUNGAL PATHOGEN, ARMILLARIA MELLEA, IN A TEMPERATE WORLDWIDE POPULATIONS

USDA-ARS?s Scientific Manuscript database

The forest pathogen Armillaria mellea s.s. (Basidiomycota, Physalacriaceae) is among the most significant forest pathogens causing root rot in northern temperate forest trees worldwide. Phylogenetic reconstructions for A. mellea show distinct European, Asian and North American lineages. The North Am...

Resistance to Phytophthora cinnamomi in the Genus Abies

Treesearch

John Frampton; Fikret Isik; Mike Benson; Jaroslav Kobliha; Jan Stjskal

2012-01-01

A major limiting factor for the culture of true firs as Christmas trees is their susceptibility to Oomycete species belonging to the genus Phytophthora. In North Carolina alone, the Fraser fir (Abies fraseri [Pursh] Poir.) Christmas tree industry loses 6 to 7 million dollars annually to root rot primarily caused by ...

Confirming QTL for aflatoxin resistance from Mp313E in different genetic backgrounds

USDA-ARS?s Scientific Manuscript database

The fungus Aspergillus flavus (Link:Fr) causes ear rot of maize (Zea mays L.) and produces the toxic metabolic product aflatoxin. One particularly effective method to control the fungus is via host plant resistance, but while several resistant breeding lines have been identified, transferring the r...

What lies beneath, unraveling the mysteries of Rhizoctonia and Pythium

USDA-ARS?s Scientific Manuscript database

Washington wheat and barley growers have long recognized that the soil-borne fungal pathogens Rhizoctonia and Pythium cause root rot, stunting and poor emergence and can chip away at yield, resulting in annual losses of 10 percent or more. Since several of these Rhizoctonia and Pythium species attac...

Host range determination and fungicide resistance assessment of Phytophthora lateralis isolates from horticultural nurseries in Oregon

Treesearch

Franziska Rupp; Ebba K. Peterson; Joyce Eberhart; Jennifer L. Parke

2017-01-01

Phytophthora lateralis causes root rot of Port-Orford cedar (Chamaecyparis lawsoniana; POC) in native forests of northwest California and southwest Oregon and in landscape plantings of horticultural Chamaecyparis cultivars in the western US and Europe. In spring 2015, following observations of mortality...

Red crown rot of Hop in Oregon caused by Phomopsis tuberivora

USDA-ARS?s Scientific Manuscript database

During July 2007, a hop grower in Marion County, Oregon reported weak growth and death of plants of cultivar Fuggle. Affected plants were aggregated within and among rows, and had underdeveloped lateral branches, uneven and weak bines, and chlorotic leaves; severely affected plants were dead. The p...

Wide variation in virulence and genetic diversity of binucleate Rhizoctonia isolates associated with root rot of strawberry in Western Australia.

PubMed

Fang, Xiangling; Finnegan, Patrick M; Barbetti, Martin J

2013-01-01

Strawberry (Fragaria×ananassa) is one of the most important berry crops in the world. Root rot of strawberry caused by Rhizoctonia spp. is a serious threat to commercial strawberry production worldwide. However, there is no information on the genetic diversity and phylogenetic status of Rhizoctonia spp. associated with root rot of strawberry in Australia. To address this, a total of 96 Rhizoctonia spp. isolates recovered from diseased strawberry plants in Western Australia were characterized for their nuclear condition, virulence, genetic diversity and phylogenetic status. All the isolates were found to be binucleate Rhizoctonia (BNR). Sixty-five of the 96 BNR isolates were pathogenic on strawberry, but with wide variation in virulence, with 25 isolates having high virulence. Sequence analysis of the internal transcribed spacers of the ribosomal DNA separated the 65 pathogenic BNR isolates into six distinct clades. The sequence analysis also separated reference BNR isolates from strawberry or other crops across the world into clades that correspond to their respective anastomosis group (AG). Some of the pathogenic BNR isolates from this study were embedded in the clades for AG-A, AG-K and AG-I, while other isolates formed clades that were sister to the clades specific for AG-G, AG-B, AG-I and AG-C. There was no significant association between genetic diversity and virulence of these BNR isolates. This study demonstrates that pathogenic BNR isolates associated with root rot of strawberry in Western Australia have wide genetic diversity, and highlights new genetic groups not previously found to be associated with root rot of strawberry in the world (e.g., AG-B) or in Australia (e.g., AG-G). The wide variation in virulence and genetic diversity identified in this study will be of high value for strawberry breeding programs in selecting, developing and deploying new cultivars with resistance to these multi-genetic groups of BNR.

Relevance of the main postharvest handling operations on the development of brown rot disease on stone fruits.

PubMed

Bernat, Maria; Segarra, Joan; Casals, Carla; Teixidó, Neus; Torres, Rosario; Usall, Josep

2017-12-01

Brown rot caused by Monilinia spp. is one of the most important postharvest diseases of stone fruit. The aim of this study was to evaluate the relevance of the main postharvest operations of fruit - hydrocooling, cold room, water dump, sorting and cooling tunnel - in the development of M. laxa on peaches and nectarines artificially infected 48, 24 or 2 h before postharvest operations. Commercial hydrocooling operation reduced incidence to 10% in 'Pp 100' nectarine inoculated 2 and 24 h before this operation; however, in 'Fantasia' nectarine incidence was not reduced, although lesion diameter was decreased in all studied varieties. Hydrocooling operation for 10 min and 40 mg L -1 of sodium hypochlorite reduced brown rot incidence by 50-77% in nectarines inoculated 2 h before operation; however, in peach varieties it was not reduced. Water dump operation showed reduction of incidence on nectarine infected 2 h before immersion for 30 s in clean water at 4 °C and 40 mg L -1 sodium hypochlorite; however, in peach varieties it was not reduced. Cold room, sorting and cooling tunnel operation did not reduce brown rot incidence. From all studied handling operations on stone fruit packing houses, hydrocooling is the most relevant in the development of brown rot disease. Duration of the treatment seems to be more important than chlorine concentration. In addition, hydrocooling and water dump were less relevant in peaches than in nectarines. As a general trend, hydrocooling and water dump reduced incidence on fruit with recent infections (2 or 24 h before operation); however, when infections have been established (48 h before operation) diseases were not reduced. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Potential worldwide distribution of Fusarium dry root rot in common beans based on the optimal environment for disease occurrence.

PubMed

Macedo, Renan; Sales, Lilian Patrícia; Yoshida, Fernanda; Silva-Abud, Lidianne Lemes; Lobo, Murillo

2017-01-01

Root rots are a constraint for staple food crops and a long-lasting food security problem worldwide. In common beans, yield losses originating from root damage are frequently attributed to dry root rot, a disease caused by the Fusarium solani species complex. The aim of this study was to model the current potential distribution of common bean dry root rot on a global scale and to project changes based on future expectations of climate change. Our approach used a spatial proxy of the field disease occurrence, instead of solely the pathogen distribution. We modeled the pathogen environmental requirements in locations where in-situ inoculum density seems ideal for disease manifestation. A dataset of 2,311 soil samples from commercial farms assessed from 2002 to 2015 allowed us to evaluate the environmental conditions associated with the pathogen's optimum inoculum density for disease occurrence, using a lower threshold as a spatial proxy. We encompassed not only the optimal conditions for disease occurrence but also the optimal pathogen's density required for host infection. An intermediate inoculum density of the pathogen was the best disease proxy, suggesting density-dependent mechanisms on host infection. We found a strong convergence on the environmental requirements of both the host and the disease development in tropical areas, mostly in Brazil, Central America, and African countries. Precipitation and temperature variables were important for explaining the disease occurrence (from 17.63% to 43.84%). Climate change will probably move the disease toward cooler regions, which in Brazil are more representative of small-scale farming, although an overall shrink in total area (from 48% to 49% in 2050 and 26% to 41% in 2070) was also predicted. Understanding pathogen distribution and disease risks in an evolutionary context will therefore support breeding for resistance programs and strategies for dry root rot management in common beans.

Potential worldwide distribution of Fusarium dry root rot in common beans based on the optimal environment for disease occurrence

PubMed Central

Macedo, Renan; Sales, Lilian Patrícia; Yoshida, Fernanda; Silva-Abud, Lidianne Lemes

2017-01-01

Root rots are a constraint for staple food crops and a long-lasting food security problem worldwide. In common beans, yield losses originating from root damage are frequently attributed to dry root rot, a disease caused by the Fusarium solani species complex. The aim of this study was to model the current potential distribution of common bean dry root rot on a global scale and to project changes based on future expectations of climate change. Our approach used a spatial proxy of the field disease occurrence, instead of solely the pathogen distribution. We modeled the pathogen environmental requirements in locations where in-situ inoculum density seems ideal for disease manifestation. A dataset of 2,311 soil samples from commercial farms assessed from 2002 to 2015 allowed us to evaluate the environmental conditions associated with the pathogen’s optimum inoculum density for disease occurrence, using a lower threshold as a spatial proxy. We encompassed not only the optimal conditions for disease occurrence but also the optimal pathogen’s density required for host infection. An intermediate inoculum density of the pathogen was the best disease proxy, suggesting density-dependent mechanisms on host infection. We found a strong convergence on the environmental requirements of both the host and the disease development in tropical areas, mostly in Brazil, Central America, and African countries. Precipitation and temperature variables were important for explaining the disease occurrence (from 17.63% to 43.84%). Climate change will probably move the disease toward cooler regions, which in Brazil are more representative of small-scale farming, although an overall shrink in total area (from 48% to 49% in 2050 and 26% to 41% in 2070) was also predicted. Understanding pathogen distribution and disease risks in an evolutionary context will therefore support breeding for resistance programs and strategies for dry root rot management in common beans. PMID:29107985

Widespread ability of fungi to drive quinone redox cycling for biodegradation.

PubMed

Krueger, Martin C; Bergmann, Michael; Schlosser, Dietmar

2016-06-01

Wood-rotting fungi possess remarkably diverse extracellular oxidation mechanisms, including enzymes, such as laccase and peroxidases, and Fenton chemistry. The ability to biologically drive Fenton chemistry by the redox cycling of quinones has previously been reported to be present in both ecologically diverging main groups of wood-rotting basidiomycetes. Therefore, we investigated whether it is even more widespread among fungal organisms. Screening of a diverse selection of a total of 18 ascomycetes and basidiomycetes for reduction of the model compound 2,6-dimethoxy benzoquinone revealed that all investigated strains were capable of reducing it to its corresponding hydroquinone. In a second step, depolymerization of the synthetic polymer polystyrene sulfonate was used as a proxy for quinone-dependent Fenton-based biodegradation capabilities. A diverse subset of the strains, including environmentally ubiquitous molds, white-rot fungi, as well as peatland and aquatic isolates, caused substantial depolymerization indicative for the effective employment of quinone redox cycling as biodegradation tool. Our results may also open up new paths to utilize diverse fungi for the bioremediation of recalcitrant organic pollutants. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Cyanide production by Pseudomonas fluorescens helps suppress black root rot of tobacco under gnotobiotic conditions

PubMed Central

Voisard, Christophe; Keel, Christoph; Haas, Dieter; Dèfago, Geneviève

1989-01-01

Pseudomonas fluorescens CHA0 suppresses black root rot of tobacco, a disease caused by the fungus Thielaviopsis basicola. Strain CHA0 excretes several metabolites with antifungal properties. The importance of one such metabolite, hydrogen cyanide, was tested in a gnotobiotic system containing an artificial, iron-rich soil. A cyanidenegative (hcn) mutant, CHA5, constructed by a gene replacement technique, protected the tobacco plant less effectively than did the wild-type CHA0. Complementation of strain CHA5 by the cloned wild-type hcn+ genes restored the strain's ability to suppress disease. An artificial transposon carrying the hcn+ genes of strain CHA0 (Tnhcn) was constructed and inserted into the genome of another P.fluorescens strain, P3, which naturally does not produce cyanide and gives poor plant protection. The P3::Tnhcn derivative synthesized cyanide and exhibited an improved ability to suppress disease. All bacterial strains colonized the roots similarly and did not influence significantly the survival of T.basicola in soil. We conclude that bacterial cyanide is an important but not the only factor involved in suppression of black root rot. Images PMID:16453871

Immobilization of the white-rot fungus Anthracophyllum discolor to degrade the herbicide atrazine.

PubMed

Elgueta, S; Santos, C; Lima, N; Diez, M C

2016-12-01

Herbicides cause environmental concerns because they are toxic and accumulate in the environment, food products and water supplies. There is a need to develop safe, efficient and economical methods to remove them from the environment, often by biodegradation. Atrazine is such herbicide. White-rot fungi have the ability to degrade herbicides of potential utility. This study formulated a novel pelletized support to immobilize the white-rot fungus Anthracophyllum discolor to improve its capability to degrade the atrazine using a biopurification system (BS). Different proportions of sawdust, starch, corn meal and flaxseed were used to generate three pelletized supports (F1, F2 and F3). In addition, immobilization with coated and uncoated pelletized supports (CPS and UPS, respectively) was assessed. UPS-F1 was determined as the most effective system as it provided high level of manganese peroxidase activity and fungal viability. The half-life (t 1/2 ) of atrazine decreased from 14 to 6 days for the control and inoculated samples respectively. Inoculation with immobilized A. discolor produced an increase in the fungal taxa assessed by DGGE and on phenoloxidase activity determined. The treatment improves atrazine degradation and reduces migration to surface and groundwater.

Antimicrobial activity of pyrrocidines from Acremonium zeae against endophytes and pathogens of maize.

PubMed

Wicklow, Donald T; Poling, Stephen M

2009-01-01

Acremonium zeae produces pyrrocidines A and B, which are polyketide-amino acid-derived antibiotics, and is recognized as a seedborne protective endophyte of maize which augments host defenses against microbial pathogens causing seedling blights and stalk rots. Pyrrocidine A displayed significant in vitro activity against Aspergillus flavus and Fusarium verticillioides in assays performed using conidia as inoculum, with pyrrocidine A being more active than B. In equivalent assays performed with conidia or hyphal cells as inoculum, pyrrocidine A revealed potent activity against major stalk and ear rot pathogens of maize, including F. graminearum, Nigrospora oryzae, Stenocarpella (Diplodia) maydis, and Rhizoctonia zeae. Pyrrocidine A displayed significant activity against seed-rotting saprophytes A. flavus and Eupenicillium ochrosalmoneum, as well as seed-infecting colonists of the phylloplane Alternaria alternata, Cladosporium cladosporioides, and Curvularia lunata, which produces a damaging leaf spot disease. Protective endophytes, including mycoparasites which grow asymptomatically within healthy maize tissues, show little sensitivity to pyrrocidines. Pyrrocidine A also exhibited potent activity against Clavibacter michiganense subsp. nebraskense, causal agent of Goss's bacterial wilt of maize, and Bacillus mojaviense and Pseudomonas fluorescens, maize endophytes applied as biocontrol agents, but were ineffective against the wilt-producing bacterium Pantoea stewartii.

Ketones prevent synaptic dysfunction induced by mitochondrial respiratory complex inhibitors

PubMed Central

Kim, Do Young; Vallejo, Johana; Rho, Jong M

2010-01-01

Abstract Ketones have previously shown beneficial effects in models of neurodegenerative disorders, particularly against associated mitochondrial dysfunction and cognitive impairment. However, evidence of a synaptic protective effect of ketones remains lacking. We tested the effects of ketones on synaptic impairment induced by mitochondrial respiratory complex (MRC) inhibitors using electrophysiological, reactive oxygen species (ROS) imaging and biochemical techniques. MRC inhibitors dose-dependently suppressed both population spike (PS) and field potential amplitudes in the CA1 hippocampus. Pre-treatment with ketones strongly prevented changes in the PS, whereas partial protection was seen in the field potential. Rotenone (Rot; 100 nmol/L), a MRC I inhibitor, suppressed synaptic function without altering ROS levels and PS depression by Rot was unaffected by antioxidants. In contrast, antioxidant-induced PS recovery against the MRC II inhibitor 3-nitropropionic acid (3-NP; 1 mmol/L) was similar to the synaptic protective effects of ketones. Ketones also suppressed ROS generation induced by 3-NP. Finally, ketones reversed the decreases in ATP levels caused by Rot and 3-NP. In summary, our data demonstrate that ketones can preserve synaptic function in CA1 hippocampus induced by MRC dysfunction, likely through an antioxidant action and enhanced ATP generation. PMID:20374433

Changes in cation concentrations in red spruce wood decayed by brown rot and white rot fungi

Treesearch

A. Ostrofsky; J. Jellison; K.T. Smith; W.C. Shortle

1997-01-01

Red spruce (Picea rubens Sarg.) wood blocks were incubated in modified soil block jars and inoculated with one of nine white rot or brown rot basidiomycetes. Concentrations of calcium, magnesium, potassium, iron, and aluminum were determined using inductively coupled plasma emission spectroscopy in wood incubated 0, 1.5, 4, and 8 months after...

Attempts to control Fusarium root rot of bean by seed dressing.

PubMed

Gilardi, G; Baudino, M; Gullino, M L; Garibaldi, A

2008-01-01

In summer 2006, a root rot caused by Fusarium oxysporum was observed in commercial farms on common bean (Phaseolus vulgaris) on the cv Billò and Borlotto. A study was undertaken in order to evaluate the efficacy of different biological control agents applied as seed dressing. In the presence of a medium-high disease incidence, among the biocontrol agents tested, Trichoderma harzianum T 22, Bacillus subtilis QST 713, followed by Pseudomonas chlororaphis, provided generally the best control. Their efficacy was also consistent in the different trials. Also the mixture of T. harzianum + T. viride provide a good disease control. Streptomyces griseoviridis and the 3 strains of Fusarim oxysporum, although less effective, provided a partial control of the disease. The fungicide mancozeb provided only a partial disease control.

Localizing gene regulation reveals a staggered wood decay mechanism for the brown rot fungus Postia placenta

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Jiwei; Presley, Gerald N.; Hammel, Kenneth E.

The fungi that cause brown rot of wood are essential contributors to biomass recycling in forest ecosystems. Their highly efficient cellulolytic systems, which may have practical applications, apparently depend on a combination of two mechanisms: nonselective oxidation of the lignocellulose by reactive oxygen species (ROS) coupled with hydrolysis of the polysaccharide components by a limited set of glycoside hydrolases (GHs). Since the production of strongly oxidizing ROS appears incompatible with the operation of GHs, it has been proposed that the fungi regulate ROS production by maintaining concentration gradients of the chelated metal ions they use to generate extracellular oxidants. However,more » calculations have indicated that this protective mechanism is physically infeasible. We examined a different hypothesis, that expression of ROS and GH components is temporally staggered by brown rot fungi in wood. We sectioned thin wafers of spruce and aspen that had been colonized directionally by Postia placenta and measured expression of relevant genes and some of the encoded enzymes, thus using the spatial distribution of fungal hyphae to resolve a fine-scale temporal sequence. Hierarchical clustering of gene expression for eight oxidoreductases thought to have a role in ROS production and of eight GHs revealed a zone of oxidoreductase upregulation at the hyphal front that persisted about 48 h before upregulation of the GHs. Additional evidence for differential expression was provided by localization of endoglucanase, xylanase, mannanase, and laccase activities in the colonized wood. Our results support a two-step mechanism for brown rot, in which substrate oxidation precedes enzymatic hydrolysis.« less

Localizing gene regulation reveals a staggered wood decay mechanism for the brown rot fungus Postia placenta

DOE PAGES

Zhang, Jiwei; Presley, Gerald N.; Hammel, Kenneth E.; ...

2016-09-12

The fungi that cause brown rot of wood are essential contributors to biomass recycling in forest ecosystems. Their highly efficient cellulolytic systems, which may have practical applications, apparently depend on a combination of two mechanisms: nonselective oxidation of the lignocellulose by reactive oxygen species (ROS) coupled with hydrolysis of the polysaccharide components by a limited set of glycoside hydrolases (GHs). Since the production of strongly oxidizing ROS appears incompatible with the operation of GHs, it has been proposed that the fungi regulate ROS production by maintaining concentration gradients of the chelated metal ions they use to generate extracellular oxidants. However,more » calculations have indicated that this protective mechanism is physically infeasible. We examined a different hypothesis, that expression of ROS and GH components is temporally staggered by brown rot fungi in wood. We sectioned thin wafers of spruce and aspen that had been colonized directionally by Postia placenta and measured expression of relevant genes and some of the encoded enzymes, thus using the spatial distribution of fungal hyphae to resolve a fine-scale temporal sequence. Hierarchical clustering of gene expression for eight oxidoreductases thought to have a role in ROS production and of eight GHs revealed a zone of oxidoreductase upregulation at the hyphal front that persisted about 48 h before upregulation of the GHs. Additional evidence for differential expression was provided by localization of endoglucanase, xylanase, mannanase, and laccase activities in the colonized wood. Our results support a two-step mechanism for brown rot, in which substrate oxidation precedes enzymatic hydrolysis.« less

Antagonistic activities of volatiles produced by two Bacillus strains against Monilinia fructicola in peach fruit.

PubMed

Liu, Chang; Yin, Xiaohui; Wang, Qingguo; Peng, Yong; Ma, Yurong; Liu, Pei; Shi, Jingying

2018-05-13

Brown rot caused by Monilinia fructicola is one of most serious diseases of postharvest peach fruit. The objective of this study was to select effective antagonistic bacteria against M. fructicola and evaluate the effects of these strains against brown rot. Four bacterial strains producing inhibitory volatile gas against M. fructicola were isolated from the peach rhizosphere soil. The volatiles produced by 12a (Bacillus vallismortis) and 14b (B. altitudinis) showed considerable antagonistic activities. M. fructicola showed 80.3 % and 68.4 % of mycelial growth inhibitions and cell damage in the presence of strains 12a and 14b. The inhibition rate of brown rot in peach fruit fumigated with the culture solution of 12a or 14b reached 77.1 % and 50.0 %. The volatile compounds produced by 12a and 14b were identified according to the gas chromatography-mass spectrometry analysis. Among them, 6-methyl-2-heptanone and 2-pentylfuran completely inhibited mycelial growth at 100 μL L -1 concentration. Cedrol showed strong inhibitory activity against mycelial growth at 100 μg L -1 and isodecyl methacrylate inhibited growth at high concentration. The inhibition rate of the 50 μL L -1 artificial mixture of these four volatiles was 59.3 % in vitro. These results indicate the two antagonistic bacteria and some volatiles produced by them have potential value in controlling brown rot in harvested peach fruit. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Structure of Rot, a global regulator of virulence genes in Staphylococcus aureus.

PubMed

Zhu, Yuwei; Fan, Xiaojiao; Zhang, Xu; Jiang, Xuguang; Niu, Liwen; Teng, Maikun; Li, Xu

2014-09-01

Staphylococcus aureus is a highly versatile pathogen that can infect human tissue by producing a large arsenal of virulence factors that are tightly regulated by a complex regulatory network. Rot, which shares sequence similarity with SarA homologues, is a global regulator that regulates numerous virulence genes. However, the recognition model of Rot for the promoter region of target genes and the putative regulation mechanism remain elusive. In this study, the 1.77 Å resolution X-ray crystal structure of Rot is reported. The structure reveals that two Rot molecules form a compact homodimer, each of which contains a typical helix-turn-helix module and a β-hairpin motif connected by a flexible loop. Fluorescence polarization results indicate that Rot preferentially recognizes AT-rich dsDNA with ~30-base-pair nucleotides and that the conserved positively charged residues on the winged-helix motif are vital for binding to the AT-rich dsDNA. It is proposed that the DNA-recognition model of Rot may be similar to that of SarA, SarR and SarS, in which the helix-turn-helix motifs of each monomer interact with the major grooves of target dsDNA and the winged motifs contact the minor grooves. Interestingly, the structure shows that Rot adopts a novel dimerization model that differs from that of other SarA homologues. As expected, perturbation of the dimer interface abolishes the dsDNA-binding ability of Rot, suggesting that Rot functions as a dimer. In addition, the results have been further confirmed in vivo by measuring the transcriptional regulation of α-toxin, a major virulence factor produced by most S. aureus strains.

New insights into the ecological interaction between grape berry microorganisms and Drosophila flies during the development of sour rot.

PubMed

Barata, André; Santos, Sara Correia; Malfeito-Ferreira, Manuel; Loureiro, Virgílio

2012-08-01

In this work, we studied the ecological interactions between grape berry microorganisms and Drosophila sp. flies involved in sour rot disease during grape ripening. After veráison the total microbial counts of grape berries affected by sour rot increased from about 2 log CFU/g of berries to more than 7 log CFU/g. Berry damage provoked a clear shift in yeast diversity from basidiomycetes to ascomycetous fermentative species. The latter were mostly Pichia terricola, Hanseniaspora uvarum, Candida zemplinina, and Zygoascus hellenicus. However, these species were not able to produce the metabolites characteristic of sour rot (gluconic and acetic acids) in inoculated berries. On the contrary, the acetic acid bacteria Gluconacetobacter saccharivorans produced high levels of these acids, mainly when berries were incubated in the presence of the insect Drosophila sp. Sour rot was not observed when grape bunches were physically separated from insects, even when berries were artificially injured. The wounds made in berry skin healed in the absence of insects, thus preventing the development of sour rot. Therefore, in the vineyard, the induction of sour rot depends on the contamination of wounded berries by a microbial consortium--yeasts and acetic acid bacteria--transported by drosophilid insects which disseminate sour rot among damaged berries. In the absence of these insects, plant defense mechanisms are effective and lead to skin healing, preventing disease spread. Thus, we showed that Drosophila sp. act as a vector for microorganisms associated with grape sour rot disease.

Pantoea hericii sp. nov., Isolated from the Fruiting Bodies of Hericium erinaceus.

PubMed

Rong, Chengbo; Ma, Yuanwei; Wang, Shouxian; Liu, Yu; Chen, Sanfeng; Huang, Bin; Wang, Jing; Xu, Feng

2016-06-01

Three Gram-negative, facultatively anaerobic bacterial isolates were obtained from the fruiting bodies of the edible mushroom Hericium erinaceus showing symptoms of soft rot disease in Beijing, China. Sequences of partial 16S rRNA gene placed these isolates in the genus Pantoea. Multilocus sequence analysis based on the partial sequences of atpD, gyrB, infB and rpoB revealed P. eucalypti and P. anthophila as their closest phylogenetic relatives and indicated that these isolates constituted a possible novel species. DNA-DNA hybridization studies confirmed the classification of these isolates as a novel species and phenotypic tests allowed for differentiation from the closest phylogenetic neighbours. The name Pantoea hericii sp. nov. [Type strain LMG 28847(T) = CGMCC 1.15224(T) = JZB 2120024(T)] is proposed.

Effect of Environment and Sugar Beet Genotype on Root Rot Development and Pathogen Profile During Storage.

PubMed

Liebe, Sebastian; Varrelmann, Mark

2016-01-01

Storage rots represent an economically important factor impairing the storability of sugar beet by increasing sucrose losses and invert sugar content. Understanding the development of disease management strategies, knowledge about major storage pathogens, and factors influencing their occurrence is crucial. In comprehensive storage trials conducted under controlled conditions, the effects of environment and genotype on rot development and associated quality changes were investigated. Prevalent species involved in rot development were identified by a newly developed microarray. The strongest effect on rot development was assigned to environment factors followed by genotypic effects. Despite large variation in rot severity (sample range 0 to 84%), the spectrum of microorganisms colonizing sugar beet remained fairly constant across all treatments with dominant species belonging to the fungal genera Botrytis, Fusarium, and Penicillium. The intensity of microbial tissue necrotization was strongly correlated with sucrose losses (R² = 0.79 to 0.91) and invert sugar accumulation (R² = 0.91 to 0.95). A storage rot resistance bioassay was developed that could successfully reproduce the genotype ranking observed in storage trials. Quantification of fungal biomass indicates that genetic resistance is based on a quantitative mechanism. Further work is required to understand the large environmental influence on rot development in sugar beet.

Virulence of Macrophomina phaseolina isolates in common bean (Phaseolus vulgaris) genotypes

USDA-ARS?s Scientific Manuscript database

Charcoal rot caused by Macrophomina phaseolina (Tassi) Goid, is an important disease in common beans (Phaseolus vulgaris) in the dry and warmer areas of Puerto Rico and in much of the tropics and subtropics worldwide. The virulence of three isolates from Isabela (Mph-ISA-TARS), Juana Diaz (Mph-JD) a...

Ovine pedomics: the first study of the ovine foot 16S rRNA-based microbiome

USDA-ARS?s Scientific Manuscript database

We report the first study of the bacterial microbiome of ovine interdigital skin based on 16S rRNA by pyrosequencing and conventional cloning with Sanger-sequencing. Ovine foot rot is an infectious, contagious disease of sheep that causes severe lameness and economic loss from decreased flock produc...

Phytotoxicity of the mycotoxin (±)-botryodiplodin produced by Macrophomina phaseolina to soybean and duckweed in vitro

USDA-ARS?s Scientific Manuscript database

The fungus Macrophomina phaseolina causes charcoal rot (CR), a major soybean disease. M. phaseolina also produces a toxin, (±)-botryodiplodin (Bot). Our objective was to determine if phytotoxic responses to Bot are consistent with the toxin’s mechanism of soybean root infection. Bot was tested f...